Yemen’s Iran-backed Houthi militia will escalate its attacks on ships in the Red Sea and other waters and has introduced “submarine weapons,” in continued solidarity with Palestinians in the Gaza war, the militia’s leader said on Thursday.

Houthi militants 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.

“Operations in the Red and Arabian Seas, Bab al-Mandab Strait, and the Gulf of Aden are continuing, escalating, and effective,” Abdul Malik al-Houthi added in a televised speech. He gave no details of the submarine weapons.

The group’s strikes are disrupting a route accounting for about 12 percent of global maritime traffic and forcing firms to take a longer, more expensive route around Africa.

The leader’s speech came the same day the Houthis sent shippers and insurers formal notice of what they termed a ban on vessels linked to Israel, the US and Britain from sailing in surrounding seas, seeking to reinforce their military campaign in support of Palestinians.

The Houthis’ communication, the first to the shipping industry outlining a ban, came in the form of two notices from the Houthis’ newly dubbed Humanitarian Operations Coordination Center 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 British 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 Center was established in Sanaa to coordinate the safe and peaceful passage of ships and vessels that have no connection to Israel,” a senior Houthi official told Reuters on Thursday.

Risk priced in

The attacks have disrupted global trade and reset shipping rates at a higher level. Shipping and insurance sources on Thursday said there was no change in rates since the issuance of the advisories.

“The Houthis have already targeted shipping with those links (to Israeli, US and UK commercial interests) and there is an elevated alert with sailing already,” one shipping source said.

Militant leader al-Houthi said the attacks would mirror escalations of Israel’s military operations in the Gaza Strip, and that retaliatory strikes by the US-British coalition have failed to stop its campaign.

Earlier on Thursday, two missiles set ablaze a ship some 70 nautical miles southeast of Aden, Yemen, the United Kingdom Maritime Trade Operations (UKMTO) agency said. The vessel and crew were reported safe and are proceeding to the next port of call, it said in a later update.

The UK-owned, Palau-flagged ship, the Islander, was en route to Egypt from Thailand, according British maritime security firm Ambrey and ship tracking data.

No ships have been sunk nor crew killed, however there are concerns about the fate of the Rubymar cargo vessel which was struck on Feb. 18 and its crew evacuated.

The Houthis said the Rubymar was at risk of sinking but a US defense official said it remained afloat.

Rubymar is “sitting lower still in the water,” Ambrey said. “A salvage has reportedly been attempted (yesterday), but aborted,” the firm said, adding a navigation warning to nearby ships was in place.

Options for the still floating ship are being considered, the vessel’s security company ISS-SAPU told Reuters on Thursday. ISS-SAPU was involved in assisting the rescue efforts of the crew.

Earlier on Thursday, Israel’s military also said it intercepted a target in the area of the Red Sea after sirens warning of incoming rockets and missiles sounded in the southern city of Eilat.