The crackdown comes just days after Ban renewed his call for all sides in Egypt to reconsider their actions in light of new political realities and the imperative to prevent further loss of life.

“The Secretary-General regrets that Egyptian authorities chose instead to use force to respond to the ongoing demonstrations,” his spokesperson said in a statement.

While the UN is still gathering precise information about today’s events, the statement said it appears that hundreds of people were killed or wounded in clashes between security forces and demonstrators demanding the reinstatement of deposed President Mohamed Morsy.

Ban extended his condolences to the families of those killed and his wishes for a full and speedy recovery to those injured. “In the aftermath of today’s violence, the Secretary-General urges all Egyptians to concentrate their efforts on promoting genuinely inclusive reconciliation,” his spokesperson said.

“While recognizing that political clocks do not run backwards, the Secretary-General also believes firmly that violence and incitement from any side are not the answers to the challenges Egypt faces,” he continued.

Ban knows that the vast majority of the Egyptian people are weary of disruptions to normal life caused by demonstrations and counter-demonstrations, and want their country to go forward peacefully in an Egyptian-led process towards prosperity and democracy, the statement added.

Given the country’s rich history and diversity of views and experiences, it is not unusual for Egyptians to disagree on the best approach forward, it further noted.

“What is important, in the Secretary-General’s view, is that differing views be expressed respectfully and peacefully,” the spokesperson said, adding that to Mr. Ban’s regret, “that is not what happened today.”

Egypt has been undergoing a democratic transition following the toppling of President Hosni Mubarak two years ago in the wake of mass protests. Last month, renewed protests – in which dozens of people were killed and wounded – led to the Egyptian military deposing Morsy. The Constitution was then suspended and an interim government set up.

A large number of those arrested were reported to be of Asian, African and North African origin. Many have since been released because they were found to be legally residing in Greece.

According to Greek police, around 2,000 of those rounded up were found with no papers and were placed in administrative detention. People are being held in overcrowded conditions at the Attika Aliens Police Directorate or at other police stations in Athens. Others have been transferred to police academies in Northern Greece which are being used as detention facilities.

“While Greece has the right to control migration, it does not have the right to treat people in the street like criminals purely because of the colour of their skin,” said Jezerca Tigani, Deputy Director of the Europe and Central Asia Programme.

“The scale of the police operation in Athens at the weekend raises serious concerns about discrimination on the basis of perceived ethnicity.”

According to reports some people were transferred to police stations despite showing police papers proving their legal residence in Greece.

One of the men arrested on Saturday told Amnesty International that he was held at Petrou Ralli in a room with around 170 people. He said he was only given water on the day of his arrest and later could only eat bread because religiously inappropriate food was provided. Many detainees were sleeping on the floor and because of the overcrowding many were taking it in turns to sleep.

In view of the sharp rise of racially motivated attacks against foreign nationals in the past year, Amnesty International said it is concerned that such a massive and discriminatory operation will fuel further attacks and xenophobia

“Greece may be going through financial difficulties while at the same time facing one of the highest migration flows among the EU countries, but these police sweep operations violate international human rights standards and should stop immediately,” said Jezerca Tigani.

“Such arrests may put at risk of deportation individuals who are in need of international protection but are unable to apply for asylum.”

Two men (from Guinea and Cote d’Ivoire) were arrested and detained during the recent sweep operations and sent to Attika Aliens Police Directorate (known as Petrou Ralli) where they were detained until last night when they were transferred to another facility in Northern Greece.

An Amnesty International delegation met with the two men last month while they were queueing outside Petrou Ralli to apply for asylum.

One of them told Amnesty International how he has repeatedly requested to apply for asylum during his detention at Petrou Ralli and that his requests were ignored by the police.

“The Greek authorities must ensure that anyone wishing to apply for asylum is provided with effective access to it. They must also act to ensure that immigration-related detention is used only as a last resort. Those detained should be notified of their grounds of detention and of their rights and ensured access to their lawyer and the outside world,” said Jezerca Tigani.

Asylum-seekers in Greece often face serious obstructions when attempting to access asylum procedures. The vast majority try to apply for asylum at the Attika Alien’s Police Directorate at Petrou Ralli in Athens. Only a small number of applications are registered by the authorities each week.

Long queues of asylum-seekers wait in appalling conditions for two to three days outside the Directorate to lodge asylum applications each Saturday morning.

An Amnesty International delegation witnessed the poor conditions in immigration detention centres in Athens during a recent visit to the country last week.

The organization’s delegates visited six detention facilities in Athens including Petrou Ralli. While the wings visited at Petrou Ralli were clean at the time of the visit, the facility was in need of repairs. In two other facilities, those of New and Old Elliniko, conditions were inhuman and degrading.

The new report All-Out Repression is based on first-hand field investigations by Amnesty International in Aleppo city at the end of May.

It documents how security forces and the notorious government-backed shabiha militias routinely used live fire against peaceful demonstrations, killing and injuring protesters and bystanders, including children, and hunted down the wounded, the medics who treated them, and opposition activists.

“The current onslaught on the city of Aleppo – which puts civilians even more at grave risk– is a predictable development which follows the disturbing pattern of abuses by state forces across the country,” said Donatella Rovera, Senior Crisis Response Adviser at Amnesty International, who recently spent several weeks investigating abuses in northern Syria, including in Aleppo.

The new report provides evidence that families of demonstrators and bystanders shot dead by security forces have been pressured to sign statements saying that their loved ones were killed by “armed terrorist gangs”.

Demonstrations in Aleppo, Syria’s largest city and main economic centre, started later and remained smaller than in other main towns.

As the size and frequency of these anti-government protests in Aleppo increased in recent months, the state security apparatus reacted with a characteristically reckless and brutal use of force that inevitably led to peaceful demonstrators being killed and injured.

Those arrested were routinely tortured, threatened and intimidated while in detention.

The report details a wide range of systematic, state-directed violations including the deliberate targeting of peaceful protesters and activists, the hunting down of injured protesters, the routine use of torture, the targeting of medics providing life-saving emergency treatment to the wounded, arbitrary arrests and enforced disappearances.

“The peaceful demonstrations I witnessed in different parts of the city invariably ended with security forces firing live rounds at peaceful protesters, their reckless and indiscriminate shooting often killing or injuring bystanders as well as demonstrators,” said Donatella Rovera.

In the report, Amnesty International again calls on the Security Council to ensure a human rights monitoring mission is present in the country, either by strengthening, extending and expanding the paralyzed UN Supervision Mission in Syria (UNSMIS) whose mandate ends in August, or by establishing another mechanism.

The organization reiterates its long-standing calls for the Security Council to refer the situation in Syria to the Prosecutor of the International Criminal Court (ICC), and to impose an arms embargo on Syria with the aim of stopping the flow of weapons to the Syrian government.

Amnesty International wants the Security Council to implement an asset freeze against President Bashar al-Assad and others who may be involved in ordering or perpetrating crimes under international law.

With the crisis in Syria turning into internal armed conflict and with rising reports of abuses by the armed opposition, Amnesty International again calls on all governments considering the supply of arms to the Free Syrian Army (FSA) or other armed opposition groups to first carry out a rigorous risk assessment based on objective information to ensure that there is not a substantial risk those arms would be used to commit or facilitate serious violations of human rights, including crimes under international law.

Amnesty International has been able to investigate independently allegations of human rights violations on the ground in Syria, including in Aleppo and surrounding areas, and concludes that the Syrian government is responsible for mass violations amounting to crimes against humanity.

“It is manifestly evident that the Syrian government has no intention of ending, let alone investigating, these crimes. Indeed it has attempted to prevent any independent investigation of these grave abuses in Aleppo and in other parts of the country,” said Rovera.

“It is incumbent on the international community to provide justice to the Syrian people and to ensure those responsible for such grave violations and crimes are held to account.

“But only a few days ago, the Security Council again failed to agree on a resolution on Syria. The paralysis of the international community over the past 18 months has unsurprisingly resulted in the Syrian government believing it can continue to commit violations, including war crimes and crimes against humanity with impunity. The situation in Syria should be referred to the International Criminal Court without further delay.”

“More fighting is not the answer. Further militarization of this conflict will only perpetuate the devastation and prolong the suffering. A sectarian civil war would also gravely imperil Syria’s neighbours,” Ban told reporters at United Nations Headquarters in New York.

He said the “tragic and intolerable” situation in Syria was foremost on his mind during his just-concluded visits to China, south-eastern Europe and London, where he met with the Joint Special Envoy for the UN and the League of Arab States for the Syrian Crisis, Kofi Annan.

Annan is working for a peaceful resolution to the conflict, but he needs the international community’s united and concrete support to succeed, said the Secretary-General.

Ban noted that the Syrian Government is adding to its “brutal crackdown” by attacking heavily populated areas with fighter aircraft and helicopters. He also noted that the armed opposition groups have also stepped up their attacks.

“Each day, as the violence spirals, more Syrians are killed, injured, tortured or forced to flee their homes or their country,” he stated.

He voiced deep concern about the impact of shelling and use of other heavy weapons on civilians in various locations around the country, particularly in the city of Aleppo, where violence over recent days has already caused a large number of civilians to flee their homes.

Reiterating his concern about weapons of mass destruction, including chemical weapons, Ban stated that any use of such weapons would be an “outrageous crime” and a major concern for the entire international community.

“We are continuously assessing the situation and our options,” said Ban. “We have also intensified our humanitarian operations. As many as two million people are affected by violence. The only solution is a Syrian-led transition that meets the legitimate aspirations of the Syrian people.”

He added that the UN Supervision Mission in Syria (UNSMIS) remains a key tool, and the six-point plan presented by the Joint Special Envoy and the June communiqué of the UN-backed Action Group on Syria – which called for the establishment of a transitional governing body, with full executive powers, as part of important agreed principles and guidelines for a Syrian-led political transition – remain the foundations for a peaceful resolution.

Annan’s six-point plan calls for an end to violence, access for humanitarian agencies to provide relief to those in need, the release of detainees, the start of inclusive political dialogue, and unrestricted access to the country for the international media.

“I call on all sides to take immediate steps to meet the Security Council requirements, and give Syria the chance it needs to move beyond the violence and onto the path to peace,” the UN chief said.

Ban’s comments came just hours after the acting head of UNSMIS, Lieutenant General Babacar Gaye, told reporters in the Syrian capital, Damascus, that he witnessed heavy shelling in the city of Homs during a visit to the area yesterday, and voiced concern about ongoing fighting in Aleppo.

“My observers there have reported an upsurge in the violence, with helicopters, tanks and artillery being used,” Lieutenant General Gaye said. “I call on the parties, again as stated by the Joint Special Envoy, to exercise restraint and avoid further bloodshed – it is imperative that both sides respect international humanitarian law and protect civilians.”

UNSMIS is tasked with monitoring the cessation of violence in Syria, as well as monitoring and supporting the full implementation of the six-point peace plan put forward by Mr. Annan.