Houthi militants first launched drone and missile strikes on the important trade route in November in what they say is solidarity with Palestinians in Gaza.

In more than 70 attacks, they have also seized one vessel and its crew and killed at least three seafarers. "It is deplorable that innocent seafarers are being attacked while simply performing their jobs, vital jobs which keep the world warm, fed, and clothed," the world's top shipping associations said in a joint statement.

The Greek-owned Tutor coal carrier attacked by Yemen's Houthi militants in the Red Sea last week has sunk, salvagers confirmed on Wednesday. The vessel was struck with missiles and an explosive-laden remote-controlled boat, according to sources.

International naval forces have been deployed to provide mainly defensive support for ships still sailing through the Red Sea, but the attacks have increased significantly.