Over 100 people have been killed in multiple attacks claimed by the Islamic State of Iraq and the Levant group in strongholds of Syrian President Bashar al-Assad, a monitoring group said.
Reports of the attacks were aired by the Syrian state TV, which put the death toll at 65.
Simultaneous car bombs and suicide bombers in bus stations, hospitals and elsewhere in the coastal cities of Tartus and Jableh in Latakia province on Monday appeared to severely breach government defences, according to the Britain-based Syrian Observatory for Human Rights.
Footage broadcast by the state-run Ikhbariya news channel of what it said were scenes of the blasts in Jableh showed several twisted and incinerated cars and minivans.
Pictures circulated by pro-Damascus social media users showed dead bodies in the back of pick-up vans and charred body parts on the ground.
The Syrian Observatory said at least 53 people were killed in Jableh, and 48 in Tartous. At least three explosions rocked Tartus, and there were at least four in Jableh, it said.
ISIL, also known as ISIS, claimed responsibility for the attack through one of its media arms, Amaq.