Iran stands accused by Western powers of supplying drones to Russia for its war against Ukraine, with analysts saying such military cooperation is of immense interest for Tehran at a delicate moment for its theocratic leadership.The United States has denounced as "appalling" Russia's use of Iranian drones after residents of Kyiv and other cites were shaken by a spate of recent attacks.Ukraine has said around 400 Iranian drones have already been used against the civilian population of Ukraine, and Moscow has ordered around 2,000. Tehran has rejected the allegations.