BEIRUT: ISIS militants Sunday pushed into a large district in southern Damascus, clashing with rival militants just a few kilometers from the center of the Syrian capital, the extremist group and Syrian activists said.

More than two dozen militants were killed in the clashes on the edges of the Qadam neighborhood, said the Britain-based Syrian Observatory for Human Rights, which has an extensive network of activists on the ground.

The pro-ISIS Aamaq News Agency reported that ISIS fighters seized half of Qadam.

The Observatory’s Rami Abdel-Rahman said ISIS fighters were holding two streets and that fighting was continuing.

ISIS supporters posted propaganda pictures claiming to show ISIS fighters advancing in the narrow streets of Qadam. The authenticity of the images could not be confirmed independently.

ISIS has emerged as one of the most powerful forces in the battle to overthrow Syrian President Bashar Assad.

The extremist group has seized about one-third of Syria and neighboring Iraq over the past year.

Armed Islamic factions fighting forces loyal to Assad control parts of the Syrian capital and large parts of the city’s suburbs.

Earlier this year, ISIS fighters entered the Palestinian refugee camp of Yarmouk, east of Qadam, and control large parts of it.

ISIS has executed more than 90 people, a third of them civilians, over the past month in areas of war-torn Syria it controls, the Observatory reported Sunday.

The Observatory said 32 civilians were among 91 people executed for “crimes” in the militant group’s self-proclaimed caliphate between July 29 and Aug. 29.

The toll included ISIS members, rebel fighters and forces loyal to President Bashar Assad.

Witchcraft, homosexual acts and working with the U.S.-led coalition fighting ISIS in Iraq and Syria are among “crimes” the group punishes with death.

On Saturday, eight ISIS fighters were killed in a coalition air raid on Raqqa, the de facto “capital” of their caliphate.

Further west, in Aleppo province, ISIS has been fiercely attacking rebel groups and its jihadi rivals, Al-Qaeda affiliate the Nusra Front.

Late Saturday, an ISIS car bomb on Tal Rifaat in Aleppo province killed 11 fighters and eight civilians.

On Sunday, 15 civilians – among them six children – were killed in government bombardment of the major rebel bastion of Eastern Ghouta near Damascus, Abdel-Rahman told AFP.

The toll included five civilians in the town of Saqba and three in Hammourieh killed in air raids.

It also included five civilians killed by shelling in Douma, a rebel-held town devastated by regime attacks.

Also Sunday, a mortar round hit an upscale neighborhood of central Damascus, killing four people, including a girl, Syrian state TV said.

Sunday’s attack targeted the posh neighborhood of Abu Rummaneh, which houses hotels and several embassies.

Turkish jets took part in U.S.-led coalition airstrikes against ISIS in Syria for the first time Friday, the Turkish Foreign Ministry said Saturday.

Turkey last month agreed to open its strategically important air bases to the coalition, but has been reluctant to play a leading role in the fight against ISIS, fearing a backlash.