Yemen's Houthis have sent shippers and insurers formal notice of what they term a ban on vessels linked to Israel, the United States and the United Kingdom from sailing in surrounding seas, seeking to reinforce their military campaign in support of Palestinians.
The move to prohibit such ships from the Red Sea, Gulf of Aden and Arabian sea came as UK maritime agencies reported a missile attack set ablaze a cargo vessel off the southern coast of Yemen.
Iran-aligned Houthi militants in Yemen have launched repeated drone and missile strikes in the Red Sea, Bab al-Mandab Strait and Gulf of Aden since November in support of Palestinians, as the Israel-Hamas war continues and the Gaza death toll reaches almost 30,000.
The Houthi strikes have disrupted a route accounting for about 12 per cent of global maritime traffic and forcing firms to take a longer, more expensive route around Africa.
The Houthis' communication, the first to the shipping industry outlining a formalised ban, came in the form of two notices from the Houthis' newly-dubbed Humanitarian Operations Co-ordination Centre sent to shipping insurers and firms.
Ships that are wholly or partially owned by Israeli individuals or entities and Israel-flagged vessels, or are owned by US or UK individuals or entities, or sailing under their flags, are banned from the Red Sea, Gulf of Aden and Arabian Sea, Thursday's notices said.
"The Humanitarian Operations Centre was established in Sanaa to co-ordinate the safe and peaceful passage of ships and vessels that have no connection to Israel," a senior Houthi official told Reuters on Thursday.
The attacks have already sent shipping insurance premiums rocketing, and the Houthi agency's newly-formalised remit could further affect prices.
Also on Thursday, US-led coalition forces were responding to a burning ship after two missiles struck it 70 nautical miles southeast of Aden, Yemen, the United Kingdom Maritime Trade Operations (UKMTO) agency said.
The UK-owned, Palau-flagged ship was en route to Egypt from Thailand, according to maritime security firm Ambrey and ship tracking data.
Islander is the name of the vessel, two shipping sources said.
In January, US and UK forces began retaliatory strikes on Houthi facilities, although the group's attacks show little sign of abating.
"If anything, Houthis attacks on cargo ships are intensifying in the Red Sea and around the Gulf of Aden," Tamas Varga of oil broker PVM wrote in a note on Tuesday.
No ships have been sunk nor crew killed, however there are concerns about the fate of the Rubymar cargo vessel which was struck on February 18.
The Houthis said the Rubymar was at risk of sinking but a US defence official said as of Thursday the ship remained afloat.
A Houthi leader said on Thursday the group has introduced "submarine weapons" in their attacks on vessels.
"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.
