In an unprecedented joint statement, the UK, US, France, Germany, Italy and Canada have asked the Syrian regime’s allies in Moscow and Tehran to urge President Bashar al-Assad to consider a ceasefire in Aleppo in order to stem the city's “humanitarian disaster”.

“The regime’s refusal to engage in a serious political process also highlights the unwillingness of Russia and Iran ... Despite their assurances to the contrary,” the statement read.

“The urgent need now is for an immediate ceasefire to allow the United Nations to get humanitarian assistance to people in eastern Aleppo. Only a political settlement can bring peace for people in Syria.”

In a rare admission of weakness on Wednesday, rebel factions within the city also asked the UN to help implement a five-day-long truce in the fierce fighting in order to evacuate 500 seriously wounded and other civilians from besieged neighbourhoods.

The calls come as Syrian government forces and allied militias managed to retake almost three quarters of rebel-controlled territory late Tuesday night, and after a medical evacuation and aid plan proposed by the UN was vetoed by permanent Security Council members Russia and China on Monday.

A siege since August and sustained ground and aerial offensive on east Aleppo since September – which has intensified in the last two weeks – has left hundreds of people dead, decimated the area’s medical facilities, and left 250,000 civilians on the brink of starvation as winter sets in.

A World Food Programme spokesperson described the situation as Aleppo’s “slow descent into hell”.

In one conversation the The Independent had with an activist inside the rebel-controlled side of the city, it was suggested that the long-suffering people would “welcome death” rather than suffer any longer or put themselves in the hands of the regime’s feared secret police.

Captain Abdel-Salam Abdel-Razek of the Nour el-Din el-Zinki rebel group said in a statement that the future of the city could be negotiated during the proposed humanitarian pause, which the coalition of rebel factions wants the UN to monitor.

Dahiyet al-Assad - Aleppo Show all 16 1 /16 Dahiyet al-Assad - Aleppo Dahiyet al-Assad - Aleppo A girl who fled areas of conflict rides a vehicle in Dahiyet al-Assad, west Aleppo city, Syria REUTERS/Ammar Abdullah Dahiyet al-Assad - Aleppo Rebel fighters from the Jaish al-Fatah (or Army of Conquest) brigade have a tea in a building under construction Getty Dahiyet al-Assad - Aleppo A rebel fighters' armoured vehicle in Dahiyet al-Assad Reuters Dahiyet al-Assad - Aleppo Rebel fighters from the Jaish al-Fatah (or Army of Conquest) brigades sit on a tank Getty Dahiyet al-Assad - Aleppo Abandoned magazine of shells after rebel fighters took control of Dahiyet al-Assad Reuters Dahiyet al-Assad - Aleppo Rebel fighters ride a pick-up truck with civilians who fled areas of conflict in Dahiyet al-Assad, west Aleppo city, Syria Reuters Dahiyet al-Assad - Aleppo A rebel fighter gestures with a girl who fled areas of conflict while they ride a pick-up truck in Dahiyet al-Assad Reuters Dahiyet al-Assad - Aleppo Smoke rises near a damaged road in Dahiyet al-Assad, west Aleppo city, Syria Reuters Dahiyet al-Assad - Aleppo Syrians carry their belongings as they leave the southwestern frontline neighbourhood of Dahiyet al-,Assad Getty Dahiyet al-Assad - Aleppo A view shows a damaged minaret of a mosque after rebel fighters took control of Dahiyet al-Assad, Syria Reuters Dahiyet al-Assad - Aleppo Rebel groups have pledged to push from newly captured positions in the Dahiyet al-Assad district towards Hamdaniyeh. Rebels and allied jihadists launched a major offensive on October 28, 2016 to break through government lines and reach the 250,000 people living in the city's east Getty Dahiyet al-Assad - Aleppo Rebel groups have pledged to push from newly captured positions in the Dahiyet al-Assad district towards Hamdaniyeh Getty Dahiyet al-Assad - Aleppo Rebel fighters from the Jaish al-Fatah (or Army of Conquest) brigades hold a position at an entrance to Aleppo, in the southwestern frontline neighbourhood of Dahiyet al-Assad Getty Dahiyet al-Assad - Aleppo Smoke billows from the frontline district of Dahiyet al-Assad following an attack by rebels on Syrian regime forces in the northern city of Aleppo Getty Dahiyet al-Assad - Aleppo Syrians carry their belongings as they leave the southwestern frontline neighbourhood of Dahiyet al-Assad Getty Dahiyet al-Assad - Aleppo People who fled areas of conflict ride a pick-up truck in Dahiyet al-Assad, west Aleppo city, Syria Reuters

The rebel proposal made no mention of a surrender, as has been negotiated in other cities during Syria’s bloody five-and-a-half-year-long civil war.

While the Kremlin said on Wednesday an exit deal for rebels “remains on the agenda,” the Syrian government said earlier this week that it does not plan on accepting any truce and will instead focus on a military victory. Mr Assad has accused rebels of using previous ceasefires as an opportunity to regroup.

Seven-year-old girl tweeting from Aleppo siege pleads for help

Mr Assad’s troops, greatly assisted by Russia’s military might, are currently poised to retake control of the entire city for the first time since 2012, in what would be the most significant victory for the regime since the fall of Homs in 2014.

Damascus and Moscow maintain that civilians and fighters have always been free to leave besieged areas and travel to neighbouring rebel-held Idlib province through humanitarian corridors, although both sides have accused the other of shelling and shooting those who tried to cross the government checkpoints.