"I hope that in the next two to three days the situation in Aleppo will be resolved," Lavrov said, according to Reuters.
"I expect that the rebels will cease resistance in the next two to three days."
The battle of Aleppo ended on Tuesday, as rebels and the Syrian government agreed to a ceasefire that would ensure opposition fighters' exit from the city.
After more than four years of clashes and months of siege, the fight for Syria's once largest city came to an end in what UN Secretary-General Ban ki-Moon called "a total uncompromising military victory" by army forces.
Russia's envoy to the United Nations said on Tuesday that a deal for rebel fighters to leave their last pocket of territory in the embattled Syrian city of Aleppo did not apply to civilians.