Russia has called for a temporary truce to begin in two towns in the Damascus countryside after multiple attacks in northwestern Syria killed at least 150 people.
The Russian defence ministry wants the truce in the towns of Daraya and Eastern Ghouta to begin on Tuesday and last for 72 hours.
Monday's announcement came as the US continued to urge Russia to pressure President Bashar al-Assad's government to stop bombing opposition forces and civilians in Damascus and Aleppo.
John Kerry, the US secretary of state, spoke to his Russian counterpart, Sergey Lavrov, by phone and urged him to press the Syrian government to halt its attacks on Aleppo in the north and Daraya near Damascus.
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At least 150 people were killed on Monday in seven near-simultaneous explosions targeting bus stations, hospitals and other civilian sites in the seaside cities of Jableh and Tartus, which are Assad strongholds.
The attacks were claimed by the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) group.
The deadliest attack occurred in Jableh, where 43 people were killed when a suicide bomber detonated his explosives at the Jableh National Hospital.
Most of those killed were patients and visiting family members, the World Health Organization (WHO) said on Tuesday, adding that three doctors and nurses were also among the dead.
Jableh National Hospital, which was taking in victims from at least three other blasts in the city earlier on Monday (including one at a crowded bus station), was badly damaged and is no longer operational, WHO said.
The early morning attacks began at a bus station in Tartus, where Russia has long maintained a naval facility.
The bombings drew condemnation from around the world, with Human Rights Watch saying that targeting civilians "would appear to constitute war crimes".
Ban Ki-moon, the UN secretary general, denounced the "terrorist attacks" while France called the bombing heinous.
The Kremlin said the attacks "demonstrate yet again how fragile the situation is in Syria and the need to take energetic measures to relaunch peace talks".
The surge in violence comes as ISIL faces mounting pressure in Syria and neighbouring Iraq, where a major government offensive to retake the city of Fallujah from the group is under way.
In Washington DC, Mark Toner, state department spokesman, accused the Assad government of using air strikes and attacks on civilians to gain tactical advantage and said Russia "has a special responsibility" to rein in Syrian government forces.
He said that the US is looking to Russia to provide the pressure needed to get the government "to reconsider the fact that if this keeps up, we may be looking at a complete breakdown of the cessation", referring to a faltering truce approved in February.
World powers have struggled to rekindle UN-brokered peace negotiations which collapsed in April when Syria's opposition walked away in frustration at halting progress on the country's dire humanitarian situation.
Syria's conflict has evolved from a popular uprising to a multi-faceted war that has killed more than 270,000 people and displaced millions.
ISIL has claimed deadly attacks in the West and throughout the Middle East.
Source: Al Jazeera and agencies