A ceasefire has been declared in Syria's Eastern Ghouta, a rebel bastion near Damascus, to run from midnight last Sunday to March 20, Russia's defence ministry said.
"A 'regime of silence' has been introduced from 00:01 on March 6 to 23:59 on March 20 (Damascus time) in the area of Eastern Ghouta," the ministry said in a statement on Tuesday.
It added that "no violations" had so far been reported.
The Army of Islam (Jaish al-Islam), a powerful rebel faction, is headquartered in Eastern Ghouta, the last opposition stronghold near Damascus.
The district has faced a blistering army offensive in recent months and is near opposition-controlled areas of Damascus increasingly targeted by the government.
Hamza Bayraqdar, a spokesman for the Army of Islam, told AFP that the faction had not been notified about the ceasefire, but would not "reject any agreement to stop the bloodshed and suffering of our people".
Syria's Al-Watan daily, which is close to the government, on Tuesday quoted a "source close to the state's efforts to conclude national reconciliation in flashpoint areas" as saying he did not have "any information" on a new agreement in eastern Damascus and Eastern Ghouta.
The Syrian Observatory For Human Rights, a Britain-based monitor of the conflict, reported that raids on Tuesday hit many towns in the Eastern Ghouta district as well as rebel districts in east Damascus, killing three civilians.
But the raids stopped in the afternoon after the Russian ceasefire announcement, it said.
Syria's conflict has killed more than 310,000 people since 2011. Russia began a bombing campaign in support of Syrian President Bashar al-Assad in September 2015.