Al-Shaar, Aleppo
Syria's five-year civil war has claimed more than 250,000 livesReuters

Russia has mooted 1 March as a potential date for a ceasefire between rebel factions and Bashar al-Assad's army in Syria. The fiercest fighting is taking place in Aleppo where government forces are advancing rapidly.

The siege in the northern city, which was Syria's most populous before the beginning of the civil war in 2011, has led to thousands fleeing towards Turkey. The rebel forces including National Coalition of Syrian Revolutionary and Opposition Forces and Jabhat al-Nusra, have been decimated by Russian airstrikes.

In the last 10 days more than 500 people have been killed in Aleppo, with civilians accounting for 89 of the fatalities, while 300,000 people may become trapped in the city by the fighting. Figures released on 10 February by the Syrian Observatory for Human Rights show 143 government forces were killed, along with 274 opposition fighters.

An estimated 31,000 people have fled Aleppo in the past few days, with fears that up to 300,000 people could be left trapped in the city with limited access to food, water and medical treatment. Earlier this month, UN-backed peace talks in Geneva broke down between the High Negotiations Committee (HNC) – representing rebel forces – and the Syrian government.

The HNC wanted the sieges in Syria to be lifted and prisoners released, while the Syrian government was repeatedly asking for a written agenda for the talks and a full list of participants – widely thought to be a ploy for time. According to Al-Arabiya, a Western official said that Russia has made a proposal to begin a ceasefire in Syria on 1 March.

The unnamed official added that the US has expressed concerns about elements of the Russian proposal. In the past few days, rebel groups have been urging Obama and the West to do more to halt the Russian bombing raids that have been integral in Assad's advance.

The air strikes have been criticised by several UN Security Council members, who object to humanitarian access being restricted by the airstrikes. World powers are due to meet in Germany on 11 February in an effort to end the bloody conflict. The civil war in Syria has killed more than 250,000 people, with a further 11 million people fleeing their homes.