The United States and Russia have agreed to carry out joint air strikes in Syria if a newly agreed ceasefire holds for a week, Russian Foreign Minister Sergei Lavrov said Friday.

"We will jointly agree on strikes against terrorists to be carried out by the Russian and American air forces. We have agreed on the zones in which these strikes will be carried out," said Lavrov.

The truce, agreed after a day of marathon talks in Geneva between Lavrov and his US counterpart John Kerry, will come into force on Monday, the first day of the Muslim holiday of Eid al-Adha.

It will be followed by coordinated strikes against Al Nusra jihadist rebels and the Islamic State group -- if it holds for a week, Lavrov said.

"Only the Russian and American air forces will work in these zones," Lavrov said.

The Americans and their allies have been insisting that Syrian regime forces, accused of widespread civilian massacres, must stand down.

Kerry said he believed the plan would lead to talks to "stop the conflict", which has raged for more than five years, killing more than 290,000 and displacing millions.

Source: AFP