Russia said on Tuesday Russian and Syrian military planes had not launched air strikes on Aleppo since Moscow said it was suspending bombing seven days ago, contradicting reports that air strikes in some areas of the city resumed on Saturday.
Defense ministry spokesman Major-General Igor Konashenkov said Russian and Syrian planes had not even approached, let alone bombed, the devastated city since last Tuesday when Russia suspended air strikes ahead of a pause in hostilities.
"Flights over Aleppo by the Russian and Syrian air forces have been completely halted for the last seven days," said Konashenkov in a statement.
He said six humanitarian corridors in eastern Aleppo, which opened as the 48-hour ceasefire began on Thursday, were still operating. Around 50 women and children had left the city late on Monday escorted by Russian military officers, Konashenkov said.
But the Syrian Observatory for Human Rights said air strikes had resumed since the lull in fighting ended on Saturday, focusing on major frontlines, including in the city's southwest. There had been no civilian deaths from air strikes inside eastern Aleppo, the monitor said.
Ibrahim Abu al-Laith, a civil defence official in eastern Aleppo, said air strikes and shelling had hit the rebel-held half of the city near to frontlines in the past week.
"There was artillery shelling..and there were planes, the city was hit by several strikes," he said, but added that there were far fewer attacks than before the ceasefire.
"It has decreased a lot. There hasn't been a lot of bombardment," he said.
On Tuesday, districts outside the city to the west of Aleppo were hit by air strikes, the Observatory said. Air strikes had continued outside Aleppo during the ceasefire.
Aleppo, Syria's most populous city before the war, is now divided into government- and rebel-held areas. Intense bombardment by Syrian and Russian warplanes has reduced the rebel-held east of the city to ruins.
Russia has accused rebels of thwarting its efforts to evacuate civilians, saying they opened fire on those wanting to leave, but rebel groups say Syrian government forces and allies had been shelling and sniping around the corridors.
Rebels did not accept the ceasefire, which they said did nothing to alleviate the situation of those who chose to remain in eastern Aleppo, and was part of a government policy to purge cities of political opponents.
Some Western countries have repeatedly accused Russia of killing civilians during its air campaign in east Aleppo. Moscow denies this, saying it targets rebel groups inside the city.
Russian Foreign Minister Sergei Lavrov on Tuesday questioned why there was so much focus on allegations that Russia had caused civilian deaths in Aleppo rather than on Iraq, where a U.S-backed offensive is trying to take Mosul from Islamic State.
The United Nations said on Monday it has abandoned plans to evacuate patients from eastern Aleppo, something it had hoped to accomplish during last week's lull in fighting.
It blamed all parties to the conflict for obstructing its efforts.