Yemen's Huthi rebels said Sunday they targeted ships off the country's coast with missiles and drones after maritime security firms said two vessels had caught fire after being hit by projectiles.

The strikes are the latest in a flurry of attacks by the Iran-backed rebels who have been harassing ships in the Red Sea and the Gulf of Aden since November in a campaign they say is in solidarity with Palestinians amid the Gaza war.

In a statement on social media platform X, Huthi military spokesperson Yahya Saree said the rebels attacked "two ships belonging to companies that violated" directives by the group not to enter Israeli ports.

He identified the vessels as the Liberia-flagged MSC Tavvishi and the Norderney, which sails under the flag of Antigua and Barbuda.

Saree said the rebels also targeted the HMS Diamond, a British naval warship, but there was no confirmation from the United Kingdom.

The Huthi announcement came after maritime security firm Ambrey said an Antigua and Barbuda-flagged cargo ship caught fire after being hit by a missile off Yemen on Saturday night.

"The ship was heading southwest along the Gulf of Aden at a speed of 8.2kts when the forward station was struck by a missile. A fire started but was neutralised," Ambrey said in a statement.

A second missile was sighted but missed and "small boats in the vicinity opened fire on the ship" causing it to change direction to port.

"No injuries were reported," the security firm added.

The United Kingdom Maritime Trade Operations (UKMTO), run by Britain's Royal Navy, said an "unknown projectile" hit a vessel off Yemen around 2000 GMT on Saturday, starting a small fire in the mooring station that was extinguished.

"All crew are reported safe and the vessel is now proceeding to its next port of call," it said.

In a separate incident on Saturday night, the UKMTO reported another projectile struck a ship "on the aft section", resulting in a fire. No casualties were reported.

"Vessels are advised to transit with caution," it said.

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

Since January, the United States and Britain have launched retaliatory strikes on Huthi targets in Yemen in response to the attacks.

The strikes have done little to deter the Huthis, who have vowed to target US and British vessels as well as all ships heading to Israeli ports.