ISIS has claimed responsibility for attacks that killed nearly 130 people in the Syrian cities of Damascus and Homs.
The terrorist outfit detonated four explosives in southern Damascus's Sayeda Zeinab district, near the Shia Muslim shrine, killing at least 83 people.
In another attack, orchestrated in a double car bombing in Homs, 57 people were killed.
ISIS was quoted by Wall Street journal as saying: "Two knights from the knights of martyrdom took off this morning with two car bombs targeting gatherings of the apostate Nusayris. What's coming next is worse and more bitter."
UK-based monitoring group Syrian Observatory for Human Rights claimed that Russian air strikes in Aleppo have killed more than 50 ISIS fighters in the past 24 hours.
In January, the terrorist group claimed responsibility for suicide attacks in the Sayeda Zeinab district that killed roughly 60 people.
Homs was once the main centre for uprisings against the Syrian President Assad. However, the rebels left the city last year under a ceasefire deal.
Meanwhile, the US Secretary of State John Kerry said that a 'provisional agreement' on a ceasefire in Syria has been reached between the US and Russia.
Kerry said: "We have reached a provisional agreement in principle on the terms of a cessation of hostilities that could begin in the coming days. The modalities for a cessation of hostilities are now being completed. In fact, we are closer to a ceasefire today than we have been."