A picture released by the state media shows Syrian army soldiers inspecting the damage at a car bombing site in Homs city. Photograph: (AFP)
Islamic State has claimed responsibility for the attack in Tartus, which is Syrian President Bashar al-Assad's base
A series of bomb attacks rocked mostly Syrian government-controlled areas, leaving at least 48 people, Syrian media reported.
The attacks come after Turkish forces and their allies in Syria ejected Islamic State from northern Syria.
One of the bombings occurred in Tartus, a coastal city in Syria and also Syrian President Bashar al-Assad's stronghold.
Islamic State claimed responsibility for a blast against a security post in Hasakeh. The handiwork of other bombings in Tartus, Homs city and an army checkpoint outside Damascus remains unknown.
The Syrian Observatory for Human Rights, a Britain-based monitoring group, believed the attacks to be coordinated.
"Clearly these attacks were simultaneous and they all targeted security posts," Rami Abdel Rahman, the Observatory director, told AFP.
The deadliest attack occurred in Tartus, which left 30 dead and dozens injured.
All the four blasts happened between 05:00 and 06:00 GMT.
United States President Barack Obama and his Russian counterpart Vladimir Putin met to discuss the Syrian crisis in the G20 summit in China.
Later, Obama called the talks "productive", while Putin said the 90-minute discussion has led to some "alignment" on the issue.
(WION with inputs from agencies)
A string of bomb attacks hit across mostly government-controlled areas of Syria on Monday, killing several dozen people including at least 35 in President Bashar al-Assad's coastal stronghold of Tartus, state media said.
At least 48 people died in the multiple blasts, with dozens also wounded in the double bombing outside of Tartus city, which is home to a Russian naval base.
The Islamic State group claimed responsibility for one of the blasts, against a Kurdish security post in Hasakeh, but there were no immediate claims for the other attacks in Tartus, on government-held Homs city and at an army checkpoint on a road outside Damascus.
In Tartus, two blasts targeted the Arzuna bridge, "the first a car bomb and the second a suicide bomber who detonated his explosive belt when people gathered to help the wounded," according to state television.
Quoting the head of Al-Bassel hospital in Tartus, the channel said 35 people had been killed and 43 others wounded in the attack.
Tartus has been largely spared the worst violence of Syria's conflict since it began with anti-government protests in March 2011.
It has become a refuge for many Syrians fleeing the fighting that has displaced more than half the country's population.
In the northeast of the country, at least eight people were killed by a bomber on a motorbike in the city of Hasakeh, which is mostly controlled by Kurdish forces, though the regime is also present.
Syrian state media said the dead were six members of the Asayesh security forces and two civilians.
IS claimed the attack in a statement circulated on social media.
Hasakeh city has been regularly targeted by IS, including in July when a motorcycle bomber killed at least 16 people outside a bakery in the city.
Monday's bombings came after advances by Turkish forces and allied Syrian rebels expelled IS from the last stretch of the Syrian-Turkish border under their control.
The jihadist group has been losing ground to both an alliance of Kurdish and Arab fighters known as the Syrian Democratic Forces and, more recently, to a Turkish offensive involving rebels loyal to Ankara.
In central Homs city, state media said at least four people were killed in a car bomb at the entrance to Al-Zahraa, a neighbourhood whose residents mostly belong to the same Alawite sect as Assad.
Al-Zahraa has also been regularly targeted in attacks, including a devastating double bomb blast in February that killed 57 people and was claimed by IS.
State television broadcast images from the aftermath of the blast in Homs, showing rubble strewn on the streets and smoke rising from the charred remains of vehicles.
Another bomb attack was also reported on Al-Sabura road west of the capital Damascus, with state media saying one person had been killed and three wounded.
The Syrian Observatory for Human Rights, a Britain-based monitoring group, said that attack targeted a checkpoint and gave a toll of three dead.
Observatory director Rami Abdel Rahman said the dead in both the Homs and Al-Sabura road attacks were government security forces manning checkpoints.
He said the blasts appeared to be coordinated.
"Clearly these attacks were simultaneous and they all targeted security posts," he told AFP.
More than 290,000 people have been killed in Syria since its conflict erupted in March 2011, and millions displaced by the fighting.