Russia said Monday that it had ordered a daily five-hour truce for a rebel-held enclave outside Damascus, even as a more extensive cease-fire approved by the U.N. Security Council this weekend has failed to quiet Syria’s warring parties.

The “humanitarian pause” ordered by Russian President Vladimir Putin, an ally of the Syrian government, appeared to be aimed at showcasing Russia’s influence as world powers scrambled to halt some of the worst bloodshed of Syria’s civil war.

Nearly 500 people have been killed and at least 1,500 wounded in a ferocious, week-long assault by government forces against Eastern Ghouta, one of the last rebel strongholds near the capital, according to the United Nations. About 400,000 people are besieged there.

Rebels have fired a blitz of rockets and mortars in response, killing roughly two dozen people, media reports say, in some of the most intense shelling the capital has seen.

The temporary Russian-proposed truce for Eastern Ghouta would begin Tuesday and be in effect daily from 9 a.m. to 2 p.m. to “avoid civilian casualties,” Russia’s Interfax news agency reported, quoting Defense Minister Sergei Shoigu. The truce would allow for civilians to evacuate the besieged suburb via a “humanitarian corridor,” he said.

The United Nations says that more than 700 people are in need of medical evacuation from the area.

Such pauses in fighting across Syria have had varying degrees of success over the past seven years. And “humanitarian corridors” or evacuation routes — from Aleppo city to villages in Idlib — have been plagued by logistical problems and acts of sabotage, even becoming targets.

“We have every reason to remain cautious,” U.N. human rights chief Zeid Raad al-Hussein said Monday in Geneva. He slammed the international community’s failure to stop “seven years of unremitting and frightful mass killing” in Syria, the Associated Press reported.

The Security Council voted unanimously Saturday to approve a resolution calling for a 30-day cease-fire to be implemented “without delay.” But with no specific deadline and no enforcement mechanism, the resolution failed to kick-start a truce.

On Sunday, Syria’s government launched a ground offensive and a suspected chlorine bomb attack against the enclave.

Officials from Russia and Iran, which also backs Syrian President Bashar al-Assad, have said that operations against “terrorists” across Syria will continue. Those governments have long painted opponents of the Syrian regime as “terrorists,” using the presence of al-Qaeda-linked forces or Islamic State militants as a justification for launching military action.

Russian Foreign Minister Sergei Lavrov said Monday that the U.N.-backed cease-fire would begin only when “all sides have agreed how to implement” it, Reuters reported.

Nine members of the same family were reported killed in a single strike in Eastern Ghouta early Monday, according to a Britain-based war monitor, the Syrian Observatory for Human Rights. The group said that 560 people had been killed in shelling and strikes over the past nine days.

According to the U.N. Office for the Coordination of Humanitarian Affairs, there are more than 393,000 people in need of humanitarian assistance in Ghouta and 15,000 have been displaced there since January.

“Eastern Ghouta cannot wait,” U.N. Secretary General António Guterres told the U.N. Human Rights Council in Geneva on Monday. “It is high time to stop this hell on Earth.”

Roughly half a million people have been killed in Syria’s conflict and about 11 million displaced. The war has ensnared world powers and laid waste to Syria’s economy and infrastructure.

Over the course of the war, several cease-fires have been brokered at the local level — between specific rebel groups and army units — and by world powers, including between Russia and the United States and among Russia, Turkey and Iran. These agreements have been aimed at a variety of goals, including establishing a simple freeze in the fighting and allowing the unfettered delivery of aid. Many of the agreements have failed, however, and sometimes even worse violence has followed.

Turkey has deflected the calls for a cease-fire and pressed forward with a month-long operation against Syrian Kurdish fighters in the northwestern region of Afrin. Turkey’s state news agency said Monday that police and paramilitary forces had crossed into Syria in preparation for a “new battle” against the Kurdish forces, known as the YPG.

Turkey views the Syrian Kurdish forces as a potential threat, saying they have links to Kurdish separatists inside Turkey. But the YPG is backed by the United States — a NATO ally of Turkey — in fighting the remnants of the Islamic State in Syria.

The presence of multiple regional and world powers and their proxies poses a challenge for enforcing a truce in Syria. The office of French President Emmanuel Macron said Monday that he had told his Turkish counterpart, President Recep Tayyip Erdogan, that Afrin was included in the cease-fire. A U.S.-led coalition also continues to strike Islamic State militants and has deployed Special Operations forces to northern and eastern Syria to keep them at bay.

Anton Troianovski in Moscow contributed to this report.