The United Nations (UN) Security Council unanimously approved a resolution Saturday demanding a 30-day ceasefire across Syria “without delay” to deliver humanitarian aid to millions and evacuate the critically ill and wounded after a series of strikes in Damascus left more than 500 people dead in one week.

Sweden, Kuwait and many other countries had been pressing for an immediate ceasefire as deaths mount in a Syrian bombing campaign in the rebel-held suburbs of Damascus known as eastern Ghouta where the death toll in a week of bombardment rose to 500.

UN humanitarian chief Mark Lowcock welcomed the vote saying: “Words must now quickly become action ─ any cessation of hostilities must be real. Attacks must stop.” . The vote was postponed for several days of lengthy and intense negotiations to try to get support from Russia, a key Syrian ally that said repeatedly an immediate ceasefire was unrealistic.

Sponsors Kuwait and Sweden amended the resolution late on Friday in a last-minute attempt to satisfy Russia, dropping a demand that the ceasefire take effect in 72 hours.

The effort worked, though US Ambassador Nikki Haley was sharply critical of Russia for delaying the vote.

“How many mothers lost their kids to the bombing and the shellings?” due to the delay, she asked. “How many more images did we need to see of fathers holding their dead children?”

'400,000 living in hell on earth'

Earlier this week UN Secretary-General Antonio Guterres urged an immediate suspension of “all war activities” in eastern Ghouta, where he said 400,000 people are living “in hell on earth.”

Guterres welcomed the resolution's adoption and stressed his expectation that it will be “immediately implemented and sustained” so aid gets to the needy and sick, UN spokesman Stephane Dujarric said. “The UN stands ready to do its part.”

While the spotlight is on eastern Ghouta, the resolution expresses “grave distress” at the humanitarian situation there as well as throughout the country including Idlib governorate, Northern Hama governorate, Rukhban and Raqqa.

It states that urgent humanitarian assistance is now required by 13.1 million people in Syria, including 5.6m people in 1,244 communities in “acute need.” That includes 2.9m in hard-to-reach and besieged locations such as eastern Ghouta.

The resolution calls on all parties to immediately lift the sieges of populated areas including eastern Ghouta, Yarmouk, Foua and Kefraya.

On the key issue of a ceasefire, the resolution “demands that all parties cease hostilities without delay for at least 30 consecutive days throughout Syria for a durable humanitarian pause, to enable the immediate delivery of humanitarian aid and services and medical evacuations of the critically sick and wounded ... and demands that all parties engage to this end.”

The resolution also demands that a ceasefire be followed immediately by access for humanitarian aid. Sweden's UN Ambassador Olof Skoog told the council just before the vote that “the UN convoys and evacuation teams are ready to go.”

Kuwait's UN Ambassador Mansour Al-Otaiba, the current council president, said after the resolution's adoption that “it cannot end the human suffering in Syria immediately.” “However, it is a positive sign sent by the Security Council, a sign that the council is united and showed solidarity to stop the humanitarian suffering and stop hostilities immediately,” he said.

“Now we must implement this resolution to save the lives of Syrian people and to deliver humanitarian aid.”

A divided UNSC?

Since the Syrian conflict began nearly seven years ago, the Security Council has been deeply divided, with Russia backing President Bashar Assad's government and the US, Britain and France supporting the opposition. The result has almost always been paralysis and inaction.

Those divisions were evident Saturday in the tough language from the US ambassador and the reply from her Russian counterpart after the vote.

“Every minute the council waited on Russia the human suffering grew,” Haley said. “Getting to a vote became a moral responsibility for everyone, but not for Russia, not for Syria, not for Iran. I have to ask why? At least 19 health facilities have been bombed since Sunday” in eastern Ghouta.

She expressed hope that Russia's belated decision to support a ceasefire “after trying every possible way to avoid it ... will be a turning point, where Russia will join us in pushing for the political settlement to this conflict.”

Russia's UN Ambassador Vassily Nebenzia responded saying it took so much time to reach an agreement because an immediate cessation of hostilities, which was originally called for by the sponsors, was “not feasible, ... not possible.”

“What is necessary is for the demands of the Security Council to be underpinned by concrete, on-the-ground agreements,” he said. “It would be naive to think that difficult issues can be addressed overnight, momentarily. We trust that all parties with influence to bear will help to bring this about.”

Another major issue in the negotiations was an exemption the Russians sought to keep up attacks against extremist groups.

The resolution allows attacks directed at extremists from the militant Islamic State group and all Al Qaeda affiliates including the Nusra Front to continue. The Syrian government and its Russian allies say they are pursuing Islamic extremists they call “terrorists” and US-backed forces are also going after IS and Al Qaeda militants.

Nebenzia accused the US of using the fight against terrorists for “geopolitical agendas with dubious legitimacy.” Instead of “scaling-up rhetoric against Russia,” he called for the US-backed coalition to promptly end its “occupation” which would improve the humanitarian situation in Syria's north and east.

Later, he told reporters that Russia also negotiated for so long to make sure the resolution “is not used as a pretext for any military action. He pointed to “worrying comments on that in recent days, and including today some very bellicose language."

Rebel groups in Syria enclave welcome ceasefire call

The two main groups controlling Syria's rebel enclave of Eastern Ghouta have welcomed the UN Security Council demand for a ceasefire, but vowed to fight back in case of renewed attacks.

The Jaish al-Islam and Faylaq al-Rahman issued separate statements late on Saturday after the council demanded a ceasefire, following seven days of ferocious regime bombardment.

“Jaish al-Islam is committed to protecting humanitarian convoys that will enter Ghouta,” the group said in a statement.

But it warned that its fighters will “immediately respond to any violation” committed by regime forces. Faylaq al-Rahman echoed that position.

“We confirm our full commitment to the (UN) resolution... Nevertheless, we reserve the right to defend the civilians of Eastern Ghouta in case of renewed attacks,” it said in a statement.

Both Faylaq al-Rahman and Jaish al-Islam are Islamist factions founded in 2013.

They have taken part in Syria peace talks in Geneva, which were brokered by the United Nations, and in the Kazakh capital Astana, organised by regime allies Russia and Iran and rebel backer Turkey.

The two rebel groups share control of Eastern Ghouta, where Syria's former Al Qaeda affiliate is also present.

Syrian capital, its suburbs calm after UN ceasefire vote

Syrian opposition activists and residents of Damascus say the city and its embattled eastern suburbs are relatively calm following the UN Security Council's unanimous approval of a resolution demanding a 30-day ceasefire across Syria.

The activists reported few violations, including some clashes, on the southern edge of the rebel-held suburbs, known as eastern Ghouta, and two airstrikes late on Saturday, shortly after the resolution was adopted.

The Britain-based Syrian Observatory for Human Rights said Sunday no deaths have been reported since the resolution passed.

Ghouta-based opposition activist Anas al-Dimashqi says the night was calm but warplanes and drones are still flying over rebel-held areas.

Damascus residents say there's more traffic in the streets, compared with previous days.

The resolution calls on all parties to immediately lift sieges of populated areas.