Nusra, Allies Advance on Regime-Held Northern Hilltops

Al-Qaida's Syria affiliate and allied jihadists advanced on a set of strategic hilltops held by pro-regime forces in the north on Monday, a monitoring group said.

The Syrian Observatory for Human Rights said the militants battled government loyalists and briefly seized one of three hilltops in the Al-Eis area south of Aleppo city.

"The pro-government fighters pushed them back, but there are still fierce clashes as the fighters from al-Nusra Front, Jund al-Aqsa, and other groups try to advance," Observatory head Rami Abdel Rahman told AFP.

The jihadists detonated five car bombs during their offensive.

"The hilltops are important because they reinforce the regime's presence in the outskirts of Aleppo and gave them a presence near the main highway south towards Damascus," Abdel Rahman said.

Aleppo province is broken up into a complex patchwork of territories under various groups.

The Islamic State group is dominant in the east, while rebel groups -- some allied with al-Nusra -- control much of the west.

Government forces based south of Aleppo city have tried to expand their control north and east. 

Further west in Idlib province, at least 12 people were killed in an air strike believed to have been conducted by either Russian or regime planes, the Observatory reported.

The raid struck a diesel market in the town of Abu Duhur, controlled by a coalition of groups including al-Nusra.

"At least three of those killed were identified as civilians, but the rest were so badly burned that they were not identified," Abdel Rahman told AFP.

Monday was the tenth day of a landmark ceasefire across parts of the country brokered by the United States and Russia.

The truce does not include areas held by IS and al-Nusra.

More than 270,000 people have been killed in Syria since the conflict began in March 2011, evolving from widespread anti-government protests to a brutal war.