Syrian government forces have reportedly recaptured all of Aleppo’s historic ‘Old City’, pushing the last remaining rebels there out.

The British-based monitoring group, The Syrian Observatory for Human Rights, said an army advance on Tuesday and overnight, supported by heavy air strikes and shelling, caused insurgents to withdraw from the Old City.

The report indicates that Syrian President Bashar al-Assad’s regime, helped by its ally Russia, is closer than ever to what would be its biggest victory of the conflict – retaking eastern Aleppo in its entirety.

The Syrian army advance has already seen rebels lose two thirds of the besieged enclave.

#UPDATE Syrian govt forces control all of Aleppo's historic Old City after rebel fighters withdrew overnight https://t.co/mrrb5BMcXD — AFP news agency (@AFP) 7 décembre 2016

Insurgents are now calling for a five-day ceasefire, talks about Aleppo’s future, and medical and civilian evacuations.

The Kremlin however looks in no mood to back down – describing all rebels left in Aleppo as ‘terrorists’ and announcing that rebel shelling has killed a Russian military adviser there.

Over five years, the civil war has killed hundreds of thousands of people, made more than half of Syrians homeless and created the world’s worst refugee crisis.

UN & partners respond to the needs of the newly displaced in #Aleppo they can access, protection services in shelter facilities being used. pic.twitter.com/vEzA9CS0WD — UNHCR-Syria (@UNHCRinSYRIA) 6 décembre 2016

Russian Foreign Minister Sergei Lavrov is due to meet US Secretary of State John Kerry in Hamburg later on Wednesday, the Russian Foreign Ministry said.