The United States and Russia have agreed to terms for a cease-fire in Syria, marking the second formal attempt this month by world powers to halt the violence of Syria’s civil war.

The two countries announced in a joint statement Monday that they had reached a deal for a “cessation of hostilities” among the various forces in the conflict, which has resulted in the deaths of more than 200,000 people since 2011. The agreement requires all sides involved to accept the terms no later than Friday at noon, Damascus time.

“The United States and the Russian Federation together call upon all Syrian parties, regional states, and others in the international community to support the immediate cessation of violence and bloodshed in Syria,” the statement said.

President Obama and Russian President Vladimir Putin spoke by phone Monday about the agreement, the White House said.

The U.S. and Russia chair the International Syria Support Group, a 17-member organization that includes the European Union and the Arab League. The two nations say they want a diplomatic resolution to the conflict, but their support of opposing sides has stymied even the most basic of peace negotiations for months. The Americans want Syrian President Bashar al-Assad removed from power and have trained and equipped opposition militias fighting against his government, while the Russians have been bombing rebels on Assad’s behalf and supporting government troops with air power.

Syrian President Bashar al-Assad said in an interview with Spain’s El Pais published Sunday he is “definitely” prepared to recognize a ceasefire brokered by Washington and Moscow. But Assad and other Syrian government officials have repeatedly vowed to recapture territory from rebels, and that effort in the northern province of Aleppo has killed hundreds of civilians this month.

The statement said the U.S. and Russia will exchange information regarding territory and who controls what in Syria, as well as work together to prevent groups party to the cease-fire from being attacked by the Russian military and the U.S.-led coalition against the Islamic State.

The latest agreement does not apply to the fight against the extremist Islamic State group, which both countries are targeting with airstrikes in Iraq and Syria. It does not call for the U.S. or Russia to end their air campaigns against the group and others in the region that are designated by the United Nations as terrorist organizations. Over the weekend, Islamic State bombs killed more than 150 people in Syrian city of Homs and in the suburbs of Damascus.

While the agreement requires the various factions in the conflict to effectively cease all attacks against each other, diplomats have stopped short of labeling it a cease-fire. Kerry referred to this month’s first and ultimately unsuccessful attempt at halting violence as not quite a cease-fire, but a “pause.” Assad said Sunday that cease-fire was not an accurate description “because a cease-fire is between two armies or two countries—it’s better to say cessation of hostility, or, let’s say, stopping the operations.”

But a cease-fire by any other name would be as tentative. Monday’s agreement is the second attempt this month at a “cessation of hostilities.” While the initial agreement allowed humanitarian workers to reach and deliver much-needed supplies to besieged Syrian neighborhoods, it was swiftly ignored, and fighting continued in full force. Syrian state media reported Sunday that government forces had taken over 19 villages in the Aleppo province held by rebels.

U.S. Secretary of State John Kerry, speaking to reporters in Jordan on Sunday, acknowledged the difficulty of bringing such deals to fruition.

“Will every single party agree automatically?” he said. Not necessarily.”