A cessation of hostilities in Syria has been expanded to the northern city of Aleppo, the State Department said, following an agreement reached between the United States and Russia.
The expansion to Aleppo province and Aleppo city went into effect just after midnight Wednesday in Damascus (2200 GMT Tuesday), the State Department said, noting an "overall decrease in violence" since then, despite some continued fighting.
The US is coordinating with Russia to finalize monitoring efforts for the ceasefire, called on all parties to abide by the agreement and urged Russia to "press" for the Moscow-allied regime of Syrian President Bashar al-Assad to comply with the Aleppo ceasefire effort, according to the State Department.
"We expect all the parties to the cessation of hostilities to fully abide by the renewed cessation in Aleppo. That means the regime and the opposition alike," Secretary of State John Kerry said.
European Union foreign policy chief Frederica Mogherini, who met with Kerry in Washington, called the US-Russian agreement "vital for so many people inside Syria that it is simply something we cannot lose."
The Syrian government had excluded Aleppo from a temporary ceasefire that started Saturday in Damascus, nearby Eastern Ghouta and the coastal area of Latakia.
Britain, Germany and France on Wednesday had said that a ceasefire in Aleppo, where heavy fighting had raged in recent days, was a prerequisite for a return to the peace talks in Geneva between representatives of the Syrian regime and the opposition.
French Foreign Minister Jean-Marc Ayrault warned that the faltering Geneva talks would collapse without a ceasefire in Aleppo.
German Foreign Minister Frank-Walter Steinmeier urged all sides in the Syrian conflict to fully comply with the ceasefire and to give civilians in Aleppo a respite from war "after weeks of fear and despair."
"If the ceasefire is kept, that's not just a big relief for the people of Aleppo," he said. "It's also an important pillar for resuming the Geneva negotiations as quickly as possible between the Assad regime and the Syrian opposition."
After the ceasefire was announced, State Department spokesman Mark Toner said that getting the cessation of hostilities back into force should be followed by a reduction in fighting, increased humanitarian aid and getting political negotiations back on track to end the conflict.
"That's what we're striving towards. That's the goal here, and not just in Aleppo, but throughout Syria," Toner said.
Earlier, as the US-Russian talks were under way, Syrian government forces regained control of positions in western Aleppo, beating back a strong rebel offensive before fighting died down Wednesday morning, said Rami Abdel-Rahman, head of the Syrian Observatory for Human Rights.
The death toll from the clashes was unclear but was in the dozens, he said.
In the regime-held western sector of Aleppo, the Observatory reported at least three people were killed and an unspecified number of civilians injured Wednesday in shelling by rebels.
Government forces were moving to impose a siege on the rebel-held east of the city, cutting it off from the western countryside, which is also held by rebels.
Calls for the ceasefire to be extended to Aleppo were fueled by the mounting civilian death toll in the divided city, which was nearing 300 since an escalation of hostilities on April 22.
In New York, UN officials and members of the UN Security Council urged the swift and full implementation of the ceasefire agreement during an emergency meeting of the council to discuss the situation in Aleppo.
UN envoy for Syria Staffan de Mistura has been seeking support from the United States and Russia to revive an overarching cessation of violence, which went into effect in late February for most of Syria but has been frequently breached.