A senior official from Yemen’s Houthis has warned cargo ships in the Red Sea to avoid travelling toward Israel and the occupied territories, after the Iran-aligned group claimed an attack on a commercial tanker earlier in the day.

Mohamed Ali al-Houthi, head of Yemen’s Houthi supreme revolutionary committee, said that ships should avoid heading toward Israel and that any that pass Yemen should keep radios turned on, and quickly respond to Houthi attempts at communication.

Al-Houthi also warned cargo ships against “falsifying their identity” or raising flags different from the country belonging to cargo shipowner.

In solidarity with Palestinians under attack from Israel in Gaza, the Houthis are using their control of Yemen’s western seaboard, including ports such as Hodeidah, to mount attacks on what they regard as shipping linked to Israel. On Saturday, they said they would target all ships heading to Israel, regardless of their nationality, and warned international shipping companies against dealing with Israeli ports.

On Tuesday, the Houthis said they hit a Norwegian commercial tanker with a missile, in their latest protest against Israel’s bombardment of Gaza.

The Iran-aligned group attacked the tanker, the Strinda, because it was delivering crude oil to an Israeli terminal, and only did so after the ship’s crew ignored all warnings, Houthi military spokesperson Yehia Sarea said in a statement.

The tanker’s owner, Norway’s Mowinckel Chemical Tankers, said the vessel was headed for Italy with a cargo of biofuel feedstock, not crude oil. But it did acknowledge a tentative Israeli port call scheduled for January, details it had not offered in the immediate hours after the attack in the Red Sea.

“Upon the recommendation of our security advisers, it was decided to withhold this information until the vessel and her crew were in safe waters,” the company said in a statement.

The US Navy destroyer USS Mason responded to the Strinda’s distress calls and assisted the crew, which was grappling with a fire, the US military said. It said the Strinda was struck on Monday night by a land-based cruise missile fired from Houthi-controlled Yemen.

The attack caused damage but no casualties, the US military said.

Following the attack, Israel’s military said it had deployed one of its most advanced warships, a Sa’ar 6 class corvette, to the Red Sea.

Maritime sources told Reuters on Wednesday that a tanker in the Red Sea was fired on by gunmen in a speedboat and targeted with missiles.

A second commercial vessel was also approached by the speedboat in the same area though not attacked, said the British maritime security firm Ambrey and other sources.

A US defence official in Washington said the USS Mason shot down a Houthi drone on Wednesday that was launched from Yemen and was travelling in its direction as it responded to reports of an attack on a commercial vessel.

The US official said Houthis had attacked the commercial vessel Ardmore Encounter in skiffs, and that two missiles were then fired from Yemen that missed the ship. The Ardmore Encounter reported no damage or injuries and continued on its way.

It was not immediately known whether the Ardmore Encounter was one of the ships earlier reported by maritime sources to have been targeted. There was no immediate claim of responsibility.

The US is hurriedly trying to organise a larger maritime protection force based out of Bahrain to prevent the world’s busiest shipping lanes becoming blocked, and thus crippling the global economy.

Industry sources have warned that the cost of shipping goods through the Red Sea is rising as the Houthis step up their attacks, with fears that a spillover could disrupt global supplies sailing through the region.

The London insurance market has listed the southern Red Sea among its high-risk areas. Ships need to notify their insurers when sailing through such areas and pay an additional premium, typically for a seven-day cover period.

About 23,000 ships pass through the narrow Bab al-Mandab Strait connecting the Red Sea and the Gulf of Aden, said Duncan Potts, a former vice admiral with Britain’s Royal Navy and a previous maritime security commander in the Gulf.

“These attacks have the potential to become far more of a global strategic economic threat than simply a regional geopolitical one,” added Potts, who is now a director with Universal Defence and Security Solutions consultancy.

Some shipping companies have already opted to re-route their ships via the Cape of Good Hope away from the Red Sea, adding journey times and additional costs.

The US has also warned Houthi rebels that the peace plan for Yemen that was negotiated with Saudi Arabia and handed to the UN peace envoy will fail if attacks on vessels continue.