Updated

An al-Qaida group has claimed responsibility for last week's killing of 48 Syrian soldiers and nine Iraqi guards in western Iraq.

The U.S.-based SITE Intelligence Group, which monitors militant forums, says al-Qaida's franchise in Iraq issued a statement on militant websites Monday claiming the attack.

The Syrian troops had sought refuge in northern Iraq during recent clashes and were being escorted back to Syria through a border crossing further south, in Iraq's western Anbar province, when they were ambushed.

The attack suggested possible coordination between al-Qaida's Iraq branch and its ideological allies in Syria who are fighting on the side of the rebels.

Syria's conflict began with anti-regime protests in March 2011 and later spiraled into civil war. The U.N. says more than 70,000 people have been killed so far.