The UN Security Council on Saturday unanimously demanded a 30-day ceasefire in Syria, as new air strikes on the rebel enclave of Eastern Ghouta took the civilian death toll from 7 days of bombing to more than 500.
With support from Russia, the Security Council approved a resolution calling for a ceasefire "without delay" to allow for humanitarian aid deliveries and medical evacuations.
After the council vote, Syrian warplanes backed by Russian air power launched new raids on Eastern Ghouta, the Syrian Observatory for Human Rights said.
At least 127 children are among the 519 dead in the bombing campaign that the regime launched last Sunday on the rebel enclave, just outside Damascus, the British-based monitor said.
At least 41 civilians were killed in Saturday's strikes, including eight children. Russia has denied taking part in the assault.
The UN vote was initially expected to be held Thursday, but was repeatedly delayed as diplomats were locked in tough negotiations to avoid a veto from Russia, which is militarily supporting President Bashar Al-Assad.
"Every minute the council waited on Russia, the human suffering grew," US ambassador Nikki Haley told the council after the vote, accusing Moscow of stalling.
"As they dragged out the negotiations, the bombs from Assad's fighter jets continued to fall. In the three days it took us to adopt this resolution, how many mothers lost their kids to the bombing and the shelling?"
Russian Ambassador Vassily Nebenzia rejected accusations of foot-dragging, saying that negotiations were needed to arrive at a demand for a ceasefire that was "feasible."
CONCESSIONS TO RUSSIA
To win Russia's approval, language specifying that the ceasefire would start 72 hours after the adoption was scrapped, replaced by "without delay," and the term "immediate" was also dropped in reference to the aid deliveries and evacuations.
In another concession to Moscow, the resolution said the ceasefire will not apply to operations against the Islamic State group or Al-Qaeda, along with "individuals, groups, undertakings and entities" associated with the terror groups.
That would allow the Syrian government offensive to continue against Al-Qaeda-linked jihadists in Idlib, the last province in Syria outside the control of Damascus.
French Ambassador Francois Delattre said it was now important to work to ensure that the ceasefire turns into reality on the ground, vowing to be "extremely vigilant... in the hours to come and the days to come."
"Nothing would be worse than seeing this resolution remain a dead letter," he said.
UN Secretary-General Antonio Guterres, who has described Eastern Ghouta as "hell on earth," is to report to the council in 15 days on the ceasefire.
Russia has vetoed 11 draft resolutions throughout the Syrian conflict to block action that targeted its ally. In November, it used its veto to end a UN-led investigation of chemical weapons attacks in Syria.
In Eastern Ghouta, news of the UN vote on the ceasefire was greeted with a shrug.
"I don't think this decision will be implemented. It will be respected neither by the regime nor Russia," said Abu Mazen, a resident of Douma, Eastern Ghouta's main town.
"We can't trust Russia or the regime. We are used to their betrayals," he added.
Control of Eastern Ghouta is shared between two main Islamist factions, while Syria's former Al-Qaeda affiliate is also present. Russia insists there can be no ceasefire with the jihadists or their allies.
Russia has been pressing for a negotiated withdrawal of rebel fighters and their families like the one that saw the government retake full control of Syria's second city Aleppo in December 2016.
But all 3 rebel groups have refused.
World leaders have expressed outrage at the plight of civilians in Eastern Ghouta.
The enclave is surrounded by government-controlled territory, and its 400,000 residents are unwilling or unable to flee the deadly siege.
In one of the many unfolding dramas at a field hospital in Douma, a young woman amputated from the knee breastfed a 40-day-old infant who had lost his entire family in the bombings.
Food supplies have been running dry, with bread no longer available on local markets.
The cornered rebels in Eastern Ghouta have been firing back into Damascus, where 6 civilians were wounded on Saturday, state media said.
Around 20 people have been killed in eastern districts of the capital since last Sunday, according to state media, and many residents have sought temporary accommodation elsewhere for fear of a further intensification of the fighting.