The Islamic State (IS) has claimed responsibility for a series of deadly bomb attacks in Damascus and Homs, which left at least 140 people dead.
A double car bomb in Homs on Sunday killed 57 people, mostly civilians, and injured many more.
A few hours later, four blasts struck the southern Damascus suburb of Sayyida Zeinab, killing at least 83 people.
Both attacks targeted areas with large numbers of Islamic minorities, people with beliefs that the Islamic State regards as heretic.
The blasts come after US Secretary of State John Kerry said a “provisional agreement” had been reached with Russia on a partial armistice and Syrian President Bashar al-Assad told reporters that Syrian refugees should not be scared of returning home.
Meanwhile, a plan by the United Nations special envoy to Syria to create a federal state has drawn mixed reactions from opposition groups, but Russia and the Assad regime have expressed support for the idea.
More than 250,000 Syrians have been killed in the five year conflict, with 11 million people displaced from their homes, including four million who have fled abroad.