Riyadh (AFP) - Huthi rebels in Yemen are posing a threat to shipping in the strategic Bab al-Mandab strait, the Saudi-led coalition supporting the government said Sunday after an attack on an Emirati vessel.

The coalition said Shiite Huthi militiamen had attacked the vessel "on its usual route to and from (the southern port city of) Aden to transfer relief and medical aid and evacuate wounded civilians".

"Coalition air and naval forces targeted Huthi militia boats involved in the attack" near the Bab al-Mandab, it said, while "coalition forces rescued civilian passengers following the attack" on Friday night.

"This incident demonstrates Huthi tactics of terrorist attacks against civilian international navigation in the Bab al-Mandab," the coalition said in a statement.

The strait is a major shipping lane between the Red Sea and the Gulf of Aden leading into the Indian Ocean.

The rebels, in a statement posted Saturday on their sabanews.net website, claimed the attack which it said targeted and "completely destroyed" an Emirati warship with rockets as it neared Mokha on the Red Sea coast.

The United Arab Emirates military acknowledged "an incident" involving a chartered vessel under its command in the Bab al-Mandab as it was returning from a "routine" journey to Aden, further south, but it reported no casualties.

The UAE is a key member of the coalition that has been battling the Iran-backed Huthis and their allies since March last year in support of President Abedrabbo Mansour Hadi's internationally recognised government.

Since March 2015, the coalition has pushed the rebels out of much of Yemen's south, but they still control nearly all of the country's Red Sea coast as well as swathes of territory around the capital Sanaa.