Russian billionaire businessman Roman Abramovich, who owns English Premier League soccer club Chelsea, has accepted a Ukrainian request to help negotiate an end to the Russian invasion of Ukraine.Abramovich was asked by Ukraine to help mediate because of his background in Russia, where he made a fortune in the chaotic 1990s period of post-communist privatisation, a source with knowledge of the matter told Reuters in the Ukrainian capital Kyiv on condition of anonymity.Word of Abramovich's involvement in talks on the conflict first came from the Jewish News, which said Kyiv had reached out through Jewish contacts to seek his help."I can confirm Roman Abramovich was contacted by the Ukrainian side for support in achieving a peaceful resolution, and that he has been trying to help ever since," a spokeswoman for Abramovich said."Considering what is at stake, we would ask for understanding as to why we have not commented on either the situation as such or his involvement."