The "Islamic State of Iraq and the Levant" (ISIL) on Monday (August 15th) claimed responsibility for a suicide bombing that killed more than 30 Syrian opposition fighters near the Turkish border, AFP reported.

ISIL claimed the attack in a statement published on social media.

The Sunday night blast struck the Atme border crossing between Turkey and the northern Syrian province of Idlib, according to the Syrian Observatory for Human Rights.

The Observatory said the opposition fighters were travelling by bus to Turkey, then back into Syria towards the opposition stronghold of Azaz in Aleppo province.

The attack killed 32 opposition fighters as they were entering Turkey, the Observatory said, adding that the toll could rise further as other fighters remained critically wounded.

ISIL has tried to advance on opposition territory in Aleppo province, particularly the towns of Azaz and nearby Marea, for several months.

A major offensive in May saw ISIL encircle Marea, but opposition forces pushed back the assault the following month after receiving ammunition from the coalition.