RIYADH: The US military said early on Tuesday it had conducted a strike against “explosive uncrewed surface vehicles” belonging to the Houthis in Yemen on Monday afternoon.

The statement by the US Central Command, or CENTCOM, said the vehicles “presented an imminent threat to US Navy ships and merchant vessels in the region” and the action, carried out at approximately 3:30 p.m. local time, was in self-defense.

The UK Maritime Trade Operations, or UKMTO, organization said on Tuesday it had received a report of an incident west of Yemen’s Hodeidah.

The US and its allies have been conducting strikes against the Houthis who have declared a blockade of maritime traffic that supports Israel’s war on Gaza. The allies said the strikes were necessary to safeguard the security of ships in the Red Sea and to support international trade.

The US and the UK have led the attacks against the Houthis, with support provided by Australia, Bahrain, the Netherlands, New Zealand and Denmark.

Israel has been conducting a military campaign in the Gaza Strip since early October after Hamas attacked settlements in Israel killing 1,200 people and taking several hostages. The military response by Israel has killed over 27,000 people, mostly women and children, and prompted the International Court of Justice to rule that there may be a plausible case of genocide in the densely packed enclave.

The US said it does not want to escalate regional tensions but conducted strikes in Iraq and Syria last week in response to the killing of three US military personnel in Jordan. The act was in retaliation for an attack on its Tower 22 base in Jordan, which the US blames on Islamic Resistance, a coalition of anti-US groups backed by Iran.

Friday’s strikes in Iraq and Syria against Iran-back militias and the Iranian Revolutionary Guard hit 85 targets across a dozen sites and killed around 18 people.

Iraq has condemned the attacks, calling them a violation of its sovereignty, and said Washington did not consult with Baghdad before they were carried out. On Monday, the US State Department walked back a statement made shortly after the strikes that Iraq had been informed ahead of the military assault.

Tehran said it had no role in the drone strike on the base in Jordan and that the militias act independently. Before Friday’s strikes Iran’s President Ebrahim Raisi said that his country would not start a war but would act “strongly” if anyone tried to bully it.

The administration of US President Joe Biden has stopped short of attacking any targets within Iran.

The UN on Monday urged parties in the conflict to pull back from the brink and consider the “unbearable human and economic cost” of a regionwide conflagration.

During a meeting of the UN Security Council to discuss the latest escalation, the under-secretary-general for political and peacebuilding affairs, Rosemarie DiCarlo, again called for an immediate humanitarian ceasefire in Gaza and for the unconditional release of all Israeli hostages held by Hamas.

Meanwhile, US Secretary of State Antony Blinken returned to the region on his fifth tour since Israel’s latest war on Gaza. He met Crown Prince Mohammed bin Salman in Riyadh on Monday and is expected to travel to Israel, Qatar and Egypt as the US and its regional allies try to deal with a growing humanitarian disaster in Gaza.

Israel and Hamas are yet to agree on plans to release hostages in return for a humanitarian ceasefire, despite diplomatic efforts over the last few weeks.