Six explosions that killed dozens of people in Syria on Monday morning have been claimed by Islamic State, state media said.

At least 40 people are dead after the blasts hit government-controlled Homs, Tartous and al Saboura, a town west of Damascus, and Kurdish-held areas in Qamishli and Hasaka in northeastern Syria.

ISIS-affiliated news agency Amaq said the jihadist group had claimed responsibility for the attacks, which were suicide operations targeting the Syrian government and a Kurdish security force. It issued separate statements naming some of the bombers.

The deadliest blasts hit Tartous, where two explosions hit the Arzouna bridge area at the entrance to the city, killing 35 people.

Syrian state television said the first explosion was a car bomb and the second was a suicide belt detonated as rescue workers came to the scene of the first incident.

Monitoring group the Syrian Observatory for Human Rights (SOHR) said that four officers were killed in Homs where an explosion hit an army checkpoint.

Syrians state television said one person was killed and three injured at the entrance to al Saboura, but SOHR said the death count was three.

A motorbike also exploded in the centre of the northeastern city of Hasaka, killing five people including three members of the YPG-affiliated security force known as the Asayish, said the Observatory.

The Kurdish YPG militia, a critical part of the US-backed campaign against Islamic State, took near complete control of Hasaka city in late August after a week of fighting with the government.

The YPG already controls swathes of northern Syria where Kurdish groups have established de facto autonomy since the start of the Syrian war in 2011.

The Observatory said a percussion bomb also went off in the province's city of Qamishli city, but nobody was harmed. 

Qamishli has been hit by a number of militant attacks in recent months.

ISIS claimed responsibility for three terror attacks on the city in December that killed more than a dozen people. In June a suicide bomber killed three people in an attack near a church that was believed to have targeted the head of the Syriac Orthodox Church.

The explosions came as US President Barack Obama and Russian President Vladimir Putin met on Monday to discuss how to reduce violence in Syria, and a possible ceasefire deal.

"If an agreement can be reached, we want to do so urgently, because of the humanitarian situation. However, we must ensure that it is an effective agreement," a senior US administration official said.

"If we cannot get the type of agreement we want, we will walk away from that effort."

Additional reporting by Reuters.