The UN Security Council on Friday delayed a vote on a demand for a 30-day ceasefire in Syria, where pro-government warplanes have been pounding the last rebel bastion near Damascus in one of the deadliest bombing campaigns of the seven-year civil war.

A draft resolution aimed at ending the carnage in the eastern Ghouta district and elsewhere in Syria will be put up for a vote in the 15-member council at noon on Saturday, Reuters reported.

The 24-hour delay followed last-minute negotiations on the text drafted by Sweden and Kuwait after Russia, a veto-holding ally of Syrian President Bashar al-Assad, proposed new amendments on Friday. “Unbelievable that Russia is stalling a vote on a ceasefire allowing humanitarian access in Syria,” tweeted US Ambassador to the UN Nikki Haley.

Leading up to the vote, all eyes are on Russia. Moscow has customarily stood in the way of Security Council measures that might impact the interests of Assad. German Chancellor Angela Merkel and French President Emmanuel Macron asked Russian President Vladimir Putin to support the resolution.

Talks have centered on the paragraph demanding a cessation of hostilities for 30 days to allow aid access and medical evacuations. A proposal for the truce to start 72 hours after the resolution’s adoption has been watered-down to instead demand it start “without delay” in a bid to win Russian support.

Diplomats, speaking on condition of anonymity, said Moscow does not want to specify when a truce should start. The resolution needs nine votes in favor and no vetoes by Russia, China, the United States, Britain and France to be adopted.

“We’re not going to give up. … I hope that we will adopt something forceful, meaningful, impactful tomorrow,” Olof Skoog, Sweden’s UN ambassador, told reporters.

Previous ceasefires have a poor record of ending fighting in Syria, where Assad’s forces have gained the upper hand.

The towns and farms of eastern Ghouta have been under government siege since 2013, with shortages of food, water and electricity that worsened last year. Earlier on Friday, the densely populated enclave was bombed for a sixth straight day, witnesses said.

The civilian casualties and devastation there are among the worst in Syria since the government captured rebel-held parts of Aleppo in 2016. At least 462 people have been killed, including at least 99 children, and many hundreds injured, the Syrian Observatory for Human Rights monitoring group said on Friday.

Syrian state media reported one person was killed and 58 injured in rebel shelling of sites in Damascus, including a hospital. And Russian Foreign Minister Sergei Lavrov said Moscow wanted guarantees that rebel fighters will not shoot at residential areas in Damascus.

Clouding any potential ceasefire is the Syrian government’s frequently used tactic of pushing rebels to surrender their strongholds after long sieges and military offensives.

Insurgents in eastern Ghouta, where there are 400,000 persons, have vowed not to accept such a fate, ruling out an evacuation of fighters, their families and other civilians of the kind that ended rebellions in Aleppo and Homs after heavy bombardment in earlier years.