Moscow will continue military operations in the besieged and battered eastern part of Aleppo until the city is "cleared of terrorists", Russian Foreign Minister Sergei Lavrov said on Thursday.
Speaking at a news conference on a visit to Turkey after a meeting with his Turkish counterpart Mevlut Cavusoglu in the Mediterranean town of Alanya, Lavrov said Russia would continue efforts to allow humanitarian aid into Aleppo and acknowledged the need for a truce.
Ankara and Moscow have long been at odds over the war in Syria, where Russia backs the government of Syrian President Bashar al-Assad and Turkey supports rebel factions fighting to topple him.
The announcement came as mounting casualties pushed the United Nations to call once again for an end to the fighting.
"Russia and Turkey have agreed to try and de-escalate the situation," Al Jazeera’s Stefanie Dekker said, reporting from Gaziantep along the Turkey-Syria border.
"Lavrov has confirmed that the Russians are actively talking to the Syrian opposition in Aleppo to try to establish some form of truce and also some form of humanitarian access … humanitarian corridors. But from what we understand, there are no safe corridors."
The Russian military intervened in Syria's war on behalf of Assad last October, and has since helped to turn the tide of the war against the opposition.
'Nowhere to go'
Aleppo, which was Syria's biggest city before the start of the war, is largely divided between the government-held west and rebel-held east.
A Russian-backed government offensive has been particularly brutal in the east of that city, where UN officials say at least 250,000 people are under siege. Tens of thousands of civilians, mostly women and children, have been forced from their homes there since Saturday.
On Wednesday, government shelling killed at least 51 civilians - including seven children - as they tried to flee the area of Jibb al-Qubba.
Footage and images of the aftermath captured by a volunteer rescue group known as the White Helmets showed people lying in the street in pools of blood, including a woman dressed in black who had been carrying a large backpack and a small girl wearing pink boots.
READ MORE: How much longer can east Aleppo hold out?
"These people have nowhere to go. It is besieged, it is freezing … and there is active fighting on the ground," said Al Jazeera's Dekker.
Speaking at an emergency session of the UN Security Council, humanitarian chief Stephen O'Brien said he was "extremely concerned about the fate of the remaining civilians in the besieged areas of eastern Aleppo city.
"These people have been besieged for nearly 150 days now and most simply don't have the means to survive for much longer. Intensified fighting and aerial bombardment continues to occur, resulting in civilian casualties and injuries."
According to an unofficial estimate by UN special envoy Staffan de Mistura, about 400,000 Syrians have been killed in the conflict that dates back to a 2011 uprising against Assad's regime.
Close to five million have fled into neighbouring countries over the years, while six million remain internally displaced.
The UN has described the situation as the "biggest refugee and displacement crisis of our time".
Source: Al Jazeera News and Agencies