Iran - the dominant Shi’ite Muslim power which is in rivalry with Saudi Arabia and the United States’ other Sunni Arab friends - has fought decades of sectarian proxy wars in Syria, Lebanon, Iraq and Yemen. Nearly 10,000 people have since been killed in Yemen’s conflict, in what the United Nations has called the world’s worst humanitarian crisis.
Yemen accuses Iran of arming Houthi rebels with drones in violation of United Nations sanctions to allow the militants to launch attacks on Saudi Arabia. Iran supports the Houthis but denies arming them.