The U.S. military struck more than a dozen Houthi targets in Yemen Friday, going after weapons systems, bases and other equipment belonging to the Iranian-backed rebels, U.S. officials confirmed.

Military aircraft and warships bombed Houthi strongholds at approximately five locations, according to the officials.

Seven strikes hit the airport in Hodeida, a major port city, and the Katheib area, which has a Houthi-controlled military base, Houthi media said. Four more strikes hit the Seiyana area in Sanaa, the capital, and two strikes hit the Dhamar province. The Houthi media office also reported three air raids in Bayda province, southeast of Sanaa.

The strikes came days after the Houthis threatened “escalating military operations” targeting Israel after they apparently shot down a U.S. military drone flying over Yemen. Last week, the group claimed responsibility for an attack targeting American warships.

The rebels fired more than a half dozen ballistic missiles and anti-ship cruise missiles and two drones at three U.S. ships that were traveling through the Bab el-Mandeb Strait, but all were intercepted by the Navy destroyers, according to several U.S. officials.

The officials spoke on condition of anonymity to discuss details not yet publicly released.

Houthis have targeted more than 80 merchant vessels with missiles and drones since the Israel-Hamas war in Gaza started last October. They have seized one vessel and sunk two in the campaign that has also killed four sailors.

Other missiles and drones have either been intercepted by a U.S.-led coalition in the Red Sea or failed to reach their targets, which have included Western military vessels.

The group has maintained that they target ships linked to Israel, the U.S. or the United Kingdom to force an end to Israel’s campaign against Hamas in Gaza. However, many of the ships attacked have little or no connection to the conflict, including some bound for Iran.