The Houthi movement in Yemen says it has struck a US merchant ship in the Red Sea in a fresh attack targeting commercial shipping.
BBC quoted Houthi military spokesperson Yahya Sarea as saying on Wednesday that the movement's armed forces had targeted an American merchant ship named KOI with "several appropriate naval missiles".
The ship, he said, had been heading to "the ports of occupied Palestine", a phrase which is sometimes used to mean Israel.
Yemen, he added, would "not hesitate" to retaliate against "British-American escalation".
"All American and British ships in the Red and Arabian Seas are legitimate targets for the Yemeni Armed Forces as long as the American-British aggression against our country continues," the Houthi spokesman was quoted as saying by BBC.
Maritime security firm Ambrey said a vessel operating south of Yemen's port of Aden had reported an explosion on board but it did not name the ship.
Meanwhile, the US has launched new air strikes in Yemen, targeting 10 drones reportedly being set up to launch.
According to Reuters news agency, the KOI is a Liberian-flagged container ship operated by UK-based Oceonix Services. The same company's fleet includes the oil tanker Marlin Luanda, which was damaged by a missile on Saturday, BBC said.
The Houthis regard all Israeli, US and British ships as legitimate targets following Israel's war on Hamas in Gaza, and US and British targeting of Houthi missile positions in what the two countries say are efforts to protect commerce.