By Jacqueline Thomsen and Mike Scarcella (Reuters) – Ukraine has accused Russia of war crimes in the town of Bucha just outside Kyiv, with Germany, France and others expressing outrage at the images of dead civilians. The mayor of Bucha said on Saturday that 300 residents had been killed by Russian troops during a month-long occupation. Victims were seen by Reuters in a mass grave and lying in the streets. Russia’s defence ministry denied the Ukrainian allegations, saying footage and photographs showing bodies in Bucha were “yet another provocation” by the Ukrainian government. Russia has prev…