An explosion was reported near a ship off the Red Sea coast of Yemen, British maritime security agency UKMTO said Thursday, adding that both the vessel and crew are safe.

"Master reports an explosion a distance off the vessel's starboard side" west of the port city of Hodeida, the United Kingdom Maritime Trade Operations said, adding that "vessel and crew are safe and proceeding to the next port of call".

There was no immediate claim for the blast, which followed a flurry of Red Sea missile strikes by Yemen's Iran-backed Huthi rebels.

The Huthis, part of the anti-Western, anti-Israel "axis of resistance" of Iranian-backed groups, have been harassing Red Sea shipping for months, triggering US and British reprisal attacks.

The Huthis have launched more than 30 attacks on commercial shipping and naval vessels since November 19, the Pentagon said on Tuesday.

In a separate attack, maritime security firm Ambrey said a missile fired from Yemen hit a merchant vessel early Thursday.

"A merchant vessel was reportedly targeted with a 'missile' while underway... southwest of Aden, Yemen," Ambrey said, adding that "the vessel reported an explosion" on board.

"Ambrey was aware that a missile was fired from... Taez," a Yemeni province that is partly in rebel hands, the firm said.

The statement did not identify the ship or the flag it was flying.

It came after the Huthi rebels said they fired missiles at a US ship in the Gulf of Aden, south of the Red Sea, heading to Israeli ports.

The missiles "directly hit the vessel", which the rebels identified as "KOI," Huthi spokesman Yahya Saree said in a statement on social media.

The rebels say the attacks are in solidarity with the Palestinians and in protest at the Israel-Hamas war that has been raging in the Gaza Strip since October.

The attacks have prompted some shipping companies to detour around southern Africa to avoid the Red Sea, a vital route that normally carries about 12 percent of global maritime trade.