Terrorists from the Islamic State of Iraq and the Levant (ISIL) on Wednesday stormed the town of Azaz, 5km from the Syrian-Turkish border, and killed at least five FSA militants, the Syrian opposition said, adding that 100 people were taken captive.

Reports in the late evening said that fighting was continuing and getting closer to a border crossing at Bab al-Salama, which is controlled by the FSA.

The fighting is the most severe since tensions mounted earlier this year between the foreign-backed militants fighting against the Syrian government.

The fighting could pose a dilemma for the Turkish government, which has been allowing militants to cross into Syria from its territory, but may not be keen to see al-Qaeda so close to its border.

Abu Ahmad, a militant in Azaz, claimed: "The Islamic State of Iraq and the Levant has seized complete control of Azaz. They are in control of the town's entrances." 

Abu Louay al-Halabi, another militant, said the fighting broke out after the Storm of the North Brigade, an FSA unit, resisted attempts by the Islamic State of Iraq and Levant to abduct a German doctor working as a volunteer at a private hospital in Azaz.

"By taking Azaz, the Islamic State is a step closer to controlling the crossing. Its objective seems to be taking over the whole countryside north of Aleppo," he said.

The Syria-Turkey border areas have been rocked by insurgency and bomb attacks in recent days.

A bomb attack struck the Bab al-Hawa crossing on Tuesday, and Turkish fighter jets shot down a Syrian regime helicopter when it strayed into Turkish airspace on Monday.

Crisis in Syria started in March 2011, when pro-reform protests turned into a massive insurgency following the intervention of Western and regional states.

The unrest, which took in terrorist groups from across Europe, the Middle East and North Africa, has transpired as one of the bloodiest conflicts in recent history.

NTJ/NJF