Russia says a daily "humanitarian pause" will be introduced in the Syrian rebel-held enclave of eastern Ghouta starting on February 27.
Defense Minister Sergei Shoigu said on February 26 that President Vladimir Putin ordered a cessation of hostilities from 9 a.m. to 2 p.m. local time, Russian news agencies reported.
A humanitarian corridor will be opened in Ghouta to allow civilians to leave, Shoigu also said.
There was no immediate reactions from the Syrian government, rebel groups, or the United Nations.
The announcement comes after the UN Security Council on February 24 passed a resolution demanding a 30-day cease-fire "without delay" to allow aid deliveries and medical evacuations in Syria's conflict areas.
The move followed a week of intense bombardment by Syrian government forces in the besieged area near Damascus that killed more than 540 people, according to activists.
The situation there led to a growing outcry from the United Nations, Western capitals, and humanitarian groups, with UN Secretary-General Antonio Guterres calling it "hell on Earth."
Speaking at the opening of the UN Human Rights Council's annual session, Guterres said earlier on February 26 that aid agencies were ready to deliver life-saving aid and evacuate critically wounded from the enclave.
He added that Security Council resolutions were "only meaningful if they are effectively implemented and that is why I expect the resolution to be immediately implemented and sustained."
The Britain-based Syrian Observatory for Human Rights said air strikes and shelling killed nine civilians there on February 26, a day after a suspected chlorine gas attack in the rebel-held territory.
Speaking before Shoigu's announcement, Kremlin spokesman Dmitry Peskov said the situation in Ghouta was alarming and that “terrorists” there were using local civilians as “hostages.”
Meanwhile, Russian Foreign Minister Sergei Lavrov said the proposed cease-fire in Syria would take effect once all sides had agreed on how it should be implemented and insisted that the truce does not apply to "terrorist groups."
"We will never support any actions aimed at exempting terrorists from a legitimate strike," he said.
The UN resolution affirmed that the proposed cessation of hostilities would not apply to military operations against the jihadist groups Islamic State (IS), Al-Qaeda, and Al-Nusra Front.
Syria and its allies Russia and Iran often refer to Sunni rebels as "terrorists," including groups allied with Western countries and Arab states as well as extremist groups like IS.
Lavrov also said that reports of an alleged chemical attack in eastern Ghouta were "fake stories."
The Syrian government denies using chemical weapons.
On February 25, Iran said attacks on "terrorists" outside the Syrian capital would continue but that Tehran and Damascus would respect the cease-fire elsewhere in the country.
And Turkey said the truce would not affect its military offensive in the Kurdish-held enclave of Afrin in northern Syria.
During a telephone on February 26, French President Emmanuel Macron told his Turkish counterpart, Recep Tayyip Erdogan, that the proposed truce must be applied across Syria, including in Afrin, the French presidency said.
Macron and German Chancellor Angela Merkel spoke by telephone with Russian leader Vladimir Putin on February 25 about the implementation of the cease-fire, the Kremlin said.
A German government spokesman said Macron and Merkel urged Putin to put "maximum" pressure on the Syrian government to halt the fighting in eastern Ghouta, where the UN says nearly 400,000 people live.
U.S. President Donald Trump on February 23 accused Russia, Iran, and the Syrian government of being responsible for a "humanitarian disgrace" in Syria.
Russia, along with Iran, has given Assad's government crucial support throughout the 7-year-old war in Syria, which began with a government crackdown on protests. Moscow helped turn the tide of the conflict in Assad's favor by launching a campaign of air strikes in 2015 and stepping up its military presence on the ground.