Two suicide bombers detonated their explosives, killing at least two security officers in the Syrian coastal city of Tartous, Syrian state television reported after midnight on Sunday.

It said the officers were part of a security patrol that stopped the bombers, who then blew themselves up. Others were injured in the blasts, including civilians, state TV said. It gave no further details.

British-based monitoring group the Syrian Observatory for Human Rights said there had been explosions from suicide bombers in Tartous and that at least two people were killed.

Tartous has not been targeted for several months, and has largely escaped the violence that has engulfed other areas of the country.

The city is part of Syrian President Bashar al-Assad's coastal heartland.

The incident took place as a fragile Russian and Turkish-backed ceasefire, welcomed by the United Nations, entered its third day with ongoing violations including clashes and air raids.

A series of bombings in May killed scores of people in Tartous and another city on the Mediterranean coast near government-controlled territory that hosts Russian military bases.

Russia supports Assad in the nearly six-year conflict, which has killed more than 300,000 people and made more than 11 million homeless.

Rebels suffered a major defeat being driven out of their last major urban stronghold in Aleppo this month.