Israel is preparing for possible military action in Syria in case the Syrian government gives missiles or chemical weapons to the Iranian and Syrian backed Lebanese group Hezbollah, Defense Minister Ehud Barak said on Friday.

“I have instructed the military to increase its intelligence preparations and prepare what is needed so that … (if necessary) … we will be able to consider carrying out an operation,” Barak said in an interview on Channel 10 TV.

He went on to say that “the moment Syrian President Bashar al-Assad starts to fall we will conduct intelligence monitoring and will liaise with other agencies.”

Meanwhile, on Friday the United Nations Security Council unanimously approved a resolution extending the mandate of its observer mission in Syria for another 30 days.

Despite calls for new sanctions against the Syrian regime under Chapter seven of the UN charter, the Security Council on Thursday failed to adopt the resolution, owing once again to the negative votes of permanent members Russia and China.

Syrian rebels have killed four of Assad’s regime members including his brother-in-law and defense minister in Damascus and seized three border crossings with Iraq and Turkey this week, putting the Syrian leader under greater pressure in the 16-month uprising against his rule.

Meanwhile, activists claim that more than 17000 have been killed according since the unrest began in March 2011. The Syrian government blames the unrest on “armed terrorist gangs”.

Hezbollah is a powerful political party and militant group in Lebanon backed by Iran and Syria. In 2006 it fought a war with Israel in 2006

On Thursday, Barak toured the Golan Heights, a strategic plateau that Israel captured from Syria in the Middle East war in 1967. Israeli defense officials fear that the deteriorating situation in their neighbor to the north, worried it could spill across the frontier. Defense Minister Ehud Barak said Thursday that Israel would stop Syrian refugees from entering the Israeli-controlled Golan Heights if they try to flee there.

Israel’s Defence Minister told Israeli radio, “The immediate executors are people form Hezbollah, who of course have constant Iranian sponsorship.”

The tourists had arrived from Israel on a charter flight and were waiting in a bus in the car park at Burgas Airport, on the Black Sea, at the time the blast took place.

Just hours after the attack Israeli Prime Minister Benjamin Netanyahu said Iran was to blame for the attack and that “Israel will react powerfully against Iranian terror.”

A bombing on a bus with Israeli tourists in Bulgaria was likely carried out by a male suicide attacker, Bugaria’s interior minister said Thursday.

Earlier Thursday, it was reported that the death toll from the attack rose to six Israelis, after one of the wounded succumbed to his wounds in the hospital, the bus driver and the suicide bomber, according to Haaretz. 

Video surveillance in front of the airport and the investigation showed the bomber could not be distinguished among arriving Israeli tourists. “He looked like everybody else – a normal person with Bermuda shorts and a backpack,” Interior Minister Tsvetan Tsvetanov said, according to Reuters.

 About 34 wounded Israeli tourists will be flown back to Israel in the next hours, Haaretz reported.

The blast came on the 18th anniversary of a 1994 bomb attack on the headquarters of Argentina’s main Jewish organization by a Hezbollah suicide bomber, which killed 85 people, Reuters writes.

Israel and Western powers have accused Iran for developing a nuclear weapons and have not rules out military action against the Islamic Republic, while Tehran insists its nuclear program is for peaceful purposes.

Hezbollah is a powerful political party and militant group  in Lebanon backed by Iran and Syria. In 2006 it fought a war with Israel in 2006.