Houthi attacks in the Red Sea have left three crew members dead and sunk two cargo vessels in a fresh wave of assaults by the Tehran-backed group along the crucial maritime trade route.

Liberian-flagged MV Eternity C sank Wednesday after sustaining ¡°significant damage¡± and had lost all propulsion, according to the U.K. Maritime Trade Operations (UKMTO), a liaison between the U.K. Navy and commercial shipping. The Houthis claimed responsibility.

U.S. officials said some surviving crew has been kidnapped. ¡°After killing their shipmates, sinking their ship, and hampering rescue efforts, the Houthi terrorists have kidnapped many surviving crew members of the Eternity C,¡± the U.S. Embassy in Yemen said in a statement, calling for the sailors¡¯ immediate and unconditional release. The Houthi group earlier said it rescued a number of the ship¡¯s crew members, provided them with medical care and transported them to a safe location.