Yemen's Iran-backed Houthis have introduced "submarine weapons" in their attacks on seagoing vessels, which they say they are carrying out in solidarity with the Palestinians in the Gaza War, their leader said on Thursday.

"Operations in the Red and Arabian Seas, Bab al-Mandab Starit, and the Gulf of Aden are continuing, escalating, and effective," Abdulmalik al-Houthi added in a televised speech.

(Reporting by Mohammed Ghobari in Aden and Jana Choukeir and Nayera Abdallah in Cairo; Editing by Hugh Lawson)