Rebel groups fighting against forces loyal to Syrian President Bashar al-Assad in Aleppo have called for a five-day ceasefire, Reuters reported on Wednesday. This comes even as government troops backed by Russia continue to retake parts of the city, which has seen some of the heaviest fighting in the six-year-long civil war in the country.

The rebel outfits, which are backed by the United States, said the pause in hostilities would be used to evacuate children and those wounded in the fighting between the two sides. The groups also called for talks about the city’s future, following an improvement in the humanitarian situation. However, there was no mention of the rebels withdrawing their fighters from Aleppo, a pre-condition set by the Syrian government for talks.

If Aleppo is captured by Assad’s supporters, it will bring the four largest cities in Syria, as well as the country’s coastal region, back under government control, according to AP. The ceasefire offer comes as US Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov meet in Germany for talks on the subject.

On Monday, China and Russia had used their veto power to obstruct a draft resolution in the United Nations Security Council, which sought a seven-day truce in Aleppo. The opposition triggered accusations from the US, which blamed the countries for issuing a “death sentence” for innocent Syrians.

Fighting between forces loyal to the Syrian president and rebel groups intensified after a ceasefire deal broke down in September, when an aid convoy was bombed in Aleppo. More than three lakh civilians have died in the war, and nearly half the country’s population has been forced to flee.