The blasts killed at least 48 people and wounded dozens more, a day after the terrorist group lost the last stretch of the Syria-Turkey border under its control.
In China, where world powers were gathered for the G20 meeting, US President Barack Obama and Russian counterpart Vladimir Putin touted 'productive' talks and 'some alignment' on Syria.
But the two powers failed to produce an expected deal to ease the violence in Syria, where more than 290,000 people have been killed and more than half the population displaced since March 2011.
The latest carnage came in a series of blasts, the deadliest of which was a double bombing in the coastal province of Tartus, outside of the Russian naval and air force base in the area.
The bombings hit a bridge outside the provincial capital Tartus city, killing at least 35 people and wounding 43, state media said.
The 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.
In the northeastern city of Hasakeh, a bomber on a motorbike killed six members of the Kurdish security forces and two civilians.
The city is mostly controlled by Kurdish forces, though the regime is also present.
In central Homs city, the target was the Al-Zahraa neighborhood, whose residents have regularly been targeted by devastating bombings.
Four people were killed there on Monday, in a car bomb that hit a checkpoint at the district's entrance.
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.
An additional attack hit the Al-Sabura road west of the capital Damascus, with state media saying one person had been killed and three wounded.
The so-called Syrian Observatory for Human Rights, a Britain-based monitoring group, said that attack targeted a checkpoint and gave a toll of three dead.
The ISIS-affiliated Amaq agency carried a statement saying the terrorist group was behind a 'string of simultaneous suicide attacks', Daily Mail reported.
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