Damascus, Aug 22 (IANS): At least 140 fighters of the Islamic State (IS) were killed Thursday in an ambush by the Syrian army near an airbase in al-Raqqa province, a media report said.

The Syrian army ambushed the militants in the vicinity of al-Tabaqa airbase, which had been under attack by the Sunni militants since the beginning of this week to strip the government troops of their last stronghold in the northern province of al-Raqqa, Xinhua reported citing the pan-Arab Al-Mayadeen TV.

The IS fighters staged suicide car bombings in the vicinity of the airbase before dawn Thursday in a bid to storm the facility, according to the Britain-based Syrian Observatory for Human Rights.

The human rights organisation said the Syria air force backed up the soldiers in the airbase with about 15 airstrikes, adding that seven soldiers were killed in the latest flare of clashes.

The clashes came just weeks after the IS captured two key military positions in al-Raqqa, namely the Brigade 93 and Division 17.

The Islamic State, previously known as the Islamic State in Iraq and the Levant, has recently claimed to have established an "Islamic Caliphate" in parts of Syria and Iraq, threatening the stability of the region.

The militant group, led by Abu Bakr al-Baghdadi, said their goal is to establish an Islamic state in Iraq and Syria to fight the Shia-led Iraqi central government and Syrian President Bashar al-Assad, whose top ranks are from the Alawite minority, an offshoot of Shia Islam.