U.S. military forces have launched five airstrikes in Yemen’s Houthi-controlled areas, the U.S. Joint Chiefs of Staff for the Middle East (Centcom) announced today.

The US military said it bombed three mobile anti-ship cruise missiles, an unmanned submarine and an unmanned surface vessel yesterday.

“This is the first observed use of UUVs by the Houthis since the attacks began on October 23,” Centcom said.

Centcom said it had determined that the missiles and vessels posed an immediate threat to US Navy ships and commercial vessels in the area.

Since November, the Iran-backed Houthis have been targeting ships in the Red Sea and Gulf of Aden that they say are linked to Israel, in a sign of “solidarity” with Palestinians in the besieged Gaza Strip, where war between the Israeli army and the Palestinian Islamist movement Hamas since October 7. Their attacks have forced many major shipping companies to suspend the passage of their ships through this strategically important area, through which about 12% of world trade passes.