Yemen's Houthi rebels targeted two U.S. Navy warships with multiple drones and missiles as they were traveling through the Bab el-Mandeb Strait, but the attacks were not successful, the Defense Department said Tuesday.

For more than a year, U.S. warships have shot down Houthi drones and missiles, but the rebels continue to menace shipping in the Red Sea.

The attack on the ships was the latest in months of violence in the region by the Yemen rebels, who are backed by Iran and have targeted commercial shipping as well as the U.S. naval forces deployed to the region.