Russia has stopped using Iranian-made kamikaze drones in Ukraine because they don't work in cold weather, a Ukrainian official said.Winters in Ukraine can be cold, with mean temperatures often below freezing between December and March.Russia started to use the Iranian drones in October, as part of a new playbook that targeted power distribution and other critical infrastructure from afar.Iran and Russia have denied any cooperation on weapons, but Iran later admitted that it had sent Russia weapons, adding that this was before Russia's invasion of Ukraine started.The UK's ministry of defense said on November 23 that Russia was likely running out of the drones, but that it could purchase more."