The death toll in air strikes on the key northwestern Syrian city of Idlib jumped to 58 late Saturday, a monitoring group said. 

The annual hajj reached its high point on Sunday when Muslims from across the world converged on a stoney hill in Saudi Arabia, a year after the worst tragedy in the pilgrimage's history.

Syria's opposition was weighing whether to take part in a truce brokered by Russia and the United States due to start on Monday, after air strikes killed dozens in rebel-held areas.

Israeli aircraft struck Syrian army positions on Saturday after fire from its war-torn neighbor hit the Israeli-held zone of the Golan Heights earlier in the day, the military said.

The complex Syria ceasefire deal agreed by the U.S. and Russia faces numerous challenges, from the deep mistrust between rebels and regime to the web of actors drawn into the war.

Two bomb blasts outside a shopping mall in central Baghdad claimed by the Islamic State group killed at least 13 people, security and medical officials said on Saturday.

The bombings were the latest in a series of deadly attacks at Baghdad shopping centres this year that have been claimed by IS, including one that killed more than 300 people in early July.

Turkey, which has sent dozens of tanks and hundreds of troops into Syria in an unprecedented incursion, on Saturday welcomed a deal agreed by the United States and Russia for a ceasefire in its conflict-torn neighbor.

"We welcome the agreement," the foreign ministry said in a statement, saying it was essential that fighting was halted across Syria and humanitarian aid reaches those in need "from the first day" of the ceasefire on the Islamic Eid al-Adha holiday starting Monday.

A Syrian opposition umbrella group said on Saturday it welcomed a complex truce deal brokered by Moscow and Washington provided it was honored by the regime. 

"We hope this will be the beginning of the end of the civilians' ordeal," leading High Negotiations Committee member Bassma Kodmani said. 

Escalating violence in South Sudan is casting a light on Israel's murky involvement in that conflict and raising questions about Prime Minister Benjamin Netanyahu's new strategy of strengthening ties with African countries.

Netanyahu has been forging alliances across Africa in an effort he says will help blunt Palestinian diplomatic initiatives against Israel at the United Nations.

The United States and Russia reached a deal on a new Syrian ceasefire, which, if it holds, could see the first joint military effort by the two powers against jihadists.

U.S. Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov said that the truce, reached late on Friday, would come into force on Monday, the first day of the Muslim holiday of Eid al-Adha.