The search for those missing after Yemen’s Houthi rebels sank a ship in the Red Sea has ended, as at least four people are presumed dead and 11 others remain unaccounted for, the private security firms involved said Monday.

Houthi rebels in Yemen attempted to strike Israel’s Ben Gurion airport after sinking two vessels in the Red Sea this week, as the group ramps up its military pressure in support of Palestinians under Israeli fire in its bid to bring the war in Gaza to an end.

Houthi rebels in Yemen have launched a violent new wave of attacks on ships in the Red Sea, sinking two vessels and killing crew members.