Syrian rebels say they will not accept any truce brokered by Russia as ceasefire fails

The main Syrian rebel umbrella group declared a floundering ceasefire had failed and and said they would not accept any peace plan in which Russia was involved.

A statement signed by more than 30 rebel groups said that they could no longer accept Russia as a sponsor of any deal as it was a partner in "crimes against our people" involving chemical weapons launched by the government regime.

It comes after Syrian government forces pounded rebel-held Aleppo as a floundering ceasefire brokered by the US and Russia broke down.

The rebel groups said that Russia, which has backed president Bashar Assad's bombing campaigns, had effectively sanctioned the use of banned chemical weapons and napalm in the attacks.

Any refusal to involve Moscow in future deals could prove a major stumbling block, as it is a key ally to Assad and has been seen as a potential deal-maker in the conflict.

The rebels also said that the escalating Russian-backed bombing of Aleppo had rendered the ceasefire deal "futile" unless there was an immediate halt to fighting and free passage for UN humanitarian aid.

The UK foreign secretary Boris Johnson today accused Russia of prolonging the war in Syria and said it may have committed a war crime by targeting an aid convoy.

The country's intervention has changed the course of the war and allowed government forces to gain ground against rebel groups.

Assad's forces announced a major new military campaign against Aleppo on Thursday as a hard-won ceasefire deal broke down.

They have been pounding rebel-held areas of the city, where more than 250,000 civilians are trapped.