Around 288,000 children aged 0 to 15 years are being targeted in the campaign, according to a news release issued by the World Health Organization (WHO) and the UN High Commissioner for Refugees (UNHCR).

Since the first case was discovered on 17 May, laboratory tests have confirmed that four more people have polio, a highly infectious disease caused by a virus that invades the nervous system and can cause total paralysis in a matter of hours.

The first round of vaccinations will be completed today, the agencies said. The next round, which begins in one week, will target the whole refugee population in Dadaab – some 424,000 people. The campaign will have four rounds in total.

At the same time, the Kenyan Ministry of Health is also conducting a vaccination campaign among the host community population in North Eastern Province in close collaboration with WHO.

The polio outbreak in Dadaab comes after a similar outbreak in Somalia, where one case has been reported in the capital, Mogadishu. The Somali Government has expressed concern about the situation in south-central Somalia, where immunization activities have not taken place for the last three years because of the security situation.

Currently, only three countries – Nigeria, Afghanistan and Pakistan – are polio endemic.

“New arrivals continue to tell us they left their homes because of air strikes and fighting, as well as fears over the application of Sharia law; they also speak of increasing shortages of food and fuel, with traditional markets unable to operate,” a spokesperson for the Office of the UN High Commissioner for Refugees (UNHCR), Adrian Edwards, told a news briefing in Geneva.

“A lack of cereal is pushing breeders to either kill some of their animals as they have nothing else to eat, or to try to sell them. Some refugees are travelling by private car or by truck, while others have arrived from Mali on foot or by donkey,” he added. “Many newly arrived refugees are expecting additional members of their families to join them in the next days from Mali.”

Fighting between Malian Government forces and Tuareg rebels broke out in northern Mali last January, following which radical Islamists seized control of the area. The renewed clashes in the country’s north, as well as the proliferation of armed groups in the region, drought and political instability in the wake of a military coup d’état in March have uprooted hundreds of thousands of civilians over the course of the past year.

Including those displaced this month, some 147,000 Malians have found refuge in neighbouring countries since the crisis in Mali started in January last year, according to UNHCR. Inside the country, 229,000 people have been displaced – mainly from Kidal, Timbuktu, and Gao.

Over the past weekend, a United Nations team arrived in the capital, Bamako, to support the national authorities in their quest to restore Mali’s constitutional order and territorial integrity.

In his remarks to journalists, Edwards said that the immediate needs for the internally displaced, as well as for refugees, are water, food, shelter and medical care.

“Living conditions are particularly precarious for the internally displaced who are in dire need of food, but also need help with education, health, lodging as well as schooling for young children,” the spokesperson said. “UNHCR and our partners are working to address the situation through income-generating activities in Bamako – currently, humanitarian access to other areas of Mali is severely restricted by the security situation.”

More than 4,200 Malian refugees have arrived in Mauritania since 11 January. After being registered, they are being transported further inland to the Mbera refugee camp, which is already hosting 55,221 people from earlier displacements.

In Niger, there are now 1,300 new refugees, Edwards said, adding that during the same period, Burkina Faso received 1,829 new refugees – mainly ethnic Tuaregs and Songhai from the regions of Gossi, Timbuktu, Gao and Bambara Maoude.

The UN refugee agency is providing assistance to refugees in camps in Burkina Faso, Niger and Mauritania by providing clean water, sanitation and hygiene structures, food, adequate shelter, healthcare and education.

Edwards said that between October last year and today, UNHCR has relocated 4,737 refugees from the border of Burkina Faso, and that, in total, the African country is hosting 38,776 Malian refugees.

The deaths resulted from a rocket hitting a mosque in the camp, where refugees had been sheltering from other fighting in nearby suburbs of Damascus, Reuters reported citing activists.

The incident was the first reported aerial attack on the camp since the revolt against President Bashar Assad erupted in 2011.

Syria is the home of more that 500,000 Palestinian refugees, most of them living in Yarmouk. It is the largest Palestinian refugee camp in Syria.

Yarmouk was established in 1957. It occupies an area of 2.1 square kilometers to accommodate refugees who were scattering in mosques, schools and other public places.

Many of the refugees in Yarmouk are professional, working as doctors, engineers and civil servants. Others are employed as casual laborers and street vendors. Overall, living conditions in Yarmouk are far better than those of the other Palestine refugee camps in Syria.

Heavy fighting in the camp broke out 12 days ago between Palestinians loyal to Assad and Syrian rebels. The fighting intensified on Saturday with rebels gaining ground inside the camp, forcing Ahmed Jibril, a veteran leader of a Damascus-based Palestinian faction that back Assad to leave the capital with his son, according to Maan News.

According to reports, Ahmed Jibril and his son have left Yarmouk, located in the Taqaddum neighborhood in southern Damascus, for the country’s Mediterranean city of Tartous.

Jibril’s PFLP-GC has maintained strong ties to Assad throughout the uprising, unlike Hamas whose Damascus-based officials quietly pulled out of Syria a few months ago.

In a related development, Alaeddin al-Sabbagh, former head of public relations in the Syrian intelligence, has announced his defection.

He made the announcement while speaking to Al Jazeera on Sunday. He called Assad’s regime a “clinically dead” one.