US
Bellingcat says Sergeev used the cover name Sergey Fedotov when operating internationally
The men insist that they do not work for Russia's GRU military intelligence
Britain issues arrest warrants for Russian nationals on suspicion of trying to kill Skripal and his daughter
The statement came on a day of furious rhetoric between Moscow and London at the UN Security Council
The threat from the east will continue long after Britain leaves the bloc next year
Allies demand explanation from Russia for planting nerve agent in returned spy's daughter's luggage