IS-linked group leadership killed by al-Nusra Front in southern Syria

The leader of a militant Syrian faction that had allegedly pledged allegiance to the Islamic State (IS) group was killed on Sunday in a suicide attack by rival militants, a monitoring group said.

"Abu Ali al-Baridi, head of al-Yarmuk Martyrs Brigade and nicknamed 'The Uncle', was killed in a suicide attack by al-Nusra Front [al-Qaeda's Syria affiliate]," the Syrian Observatory for Human Rights said.

Observatory head Rami Abdel Rahman said Baridi and two of his group's top leaders were killed in the town of Jamlah in the southern Syrian province of Daraa bordering Jordan.

Baridi's faction pledged allegiance to IS in 2014 and operated in the south of the country, Abdel Rahman said.

Al-Nusra's official Twitter account confirmed it had attacked Baridi, calling it a "heroic infiltration operation".

The two militant factions had been clashing in Daraa "for months," Abdel Rahman told AFP, adding that al-Nusra fighters fired celebratory gunshots when they learned "The Uncle" had been killed.

Also reportedly among the dead were Abu Abdullah al-Jaouni, deputy commander of the brigade and Abu Obeida Qahtan, another prominent fighter who formerly fought in Afghanistan.

At least 32 fighters from al-Nusra, al-Yarmuk Martyrs Brigade and Islamist groups died in intra-rebel clashes in the past few days. 

"With this assassination, al-Nusra has asserted its control on the southwestern front of Daraa province, near the border with the [Israeli-occupied] Golan," Abdel Rahman said.

Daraa province is largely under opposition control and is dominated by the Southern Front alliance, while the provincial capital is divided between government and rebel forces.

Al-Nusra and IS were originally both part of al-Qaeda's network in Syria, but IS split into its own faction in early 2014 and the groups have been fighting each other ever since.

Elsewhere, 11 pro-government forces were killed on Sunday and 45 were wounded when rebels, including Islamists, attacked them in the western district of Aleppo city, the Observatory said.

The northern city, once Syria's economic hub, has been divided since mid-2012, with rebels holding the east and government forces controlling western districts.

In the central province of Homs, warplanes believed to be Russian carried out 40 air strikes Sunday, including on the ancient city of Palmyra, which IS seized in May.

The Observatory said 17 civilians were wounded in the strikes.