Yemen’s Houthi rebels have shot down what bystanders described as an American drone, potentially the latest downing of a U.S. spy drone as the militants continue their attacks on the Red Sea corridor.

U.N. experts say Yemen’s Houthi rebels have been transformed from a local armed group with limited capabilities to a powerful military organization with support from Iran, Iraqi armed groups, Lebanon’s Hezbollah militants and others.

Yemen’s Houthi rebels, once a small, limited local group, have grown into a powerful military force, largely due to support from Iran and allied forces. This transformation has shifted them from a regional movement to an influential military player with enhanced weaponry and capabilities.