On Monday Mr Hollande said he had not yet decided whether to host Mr Putin, saying that pro-government forces in Syria troops had committed a "war crime" in the city of Aleppo with Russian support.

"I asked myself the question... Is it useful? Is it necessary? Can it be a way of exerting pressure? Can we get him to stop what he is doing with the Syrian regime?" Mr Hollande said in a television interview.

Jean-Marc Ayrault, the French foreign minister, said on Monday that France would ask prosecutors at the International Criminal Court in the Hague to consider an investigation into suspected Syrian and Russian war crimes.

Mr Ayrault visited Moscow last week for talks with Sergei Lavrov, his Russian counterpart, in an attempt to win support at the UN for a French draft resolution for a ceasefire in Aleppo.