At least 40 people have been killed in four bombings in government-held areas of Syria and one in a city dominated by Kurdish forces, state media report, the BBC reports.
The attacks took place between 08:00 and 09:00 (05:00-06:00 GMT) around Damascus, Homs, Tartous and Hassakeh. It was not clear if they were linked.
The deadliest incident was outside Tartous, on the Mediterranean coast.
Tartous, which hosts a Russian naval base, is a stronghold of President Bashar al-Assad’s Alawite sect.
A news agency affiliated to the jihadist group Islamic State (IS) said it was behind the Hassakeh attack, which allegedly targeted Kurdish militiamen.