US Navy helicopters sank three vessels operated by Yemen's Iran-backed Huthi rebels that had attacked a container ship in the Red Sea, the military said Sunday.

After the Huthis fired on the US helicopters, they "returned fire in self-defense", sinking three of four small boats that had come within 20 meters of the ship, and killing the crews, the US Central Command (CENTCOM) said in a statement.

"The fourth boat fled the area," it added.

CENTCOM said the navy responded to a request for assistance from the Maersk Hangzhou, a Singapore-flagged, Denmark-owned and operated container ship that reported coming under attack for a second time in 24 hours while transiting the Red Sea.

Iranian-backed Houthi small boats attack merchant vessel and U.S. Navy helicopters in Southern Red Sea

On Dec. 31 at 6:30am (Sanaa time) the container ship MAERSK HANGZHOU issued a second distress call in less than 24 hours reporting being under attack by four Iranian-backed... pic.twitter.com/pj8NAzjbVF

— U.S. Central Command (@CENTCOM) December 31, 2023

The vessel had earlier been targeted with two anti-ship ballistic missiles that the US military shot down.

One of the missiles, both launched from Huthi-controlled Yemen, hit the Maersk Hangzhou.

The Huthis have repeatedly targeted vessels in the vital Red Sea shipping lane with strikes they say are in support of Palestinians in Gaza, where Israel is battling Hamas group.

The attacks are endangering a transit route that carries up to 12 percent of global trade, prompting the United States to set up a multinational naval task force this month to protect Red Sea shipping.

The latest round of the Israel-Hamas conflict began when the Palestinian Hamas group carried out a shock cross-border attack from Gaza on October 7 that killed about 1,140 people, mostly civilians, according to an AFP tally based on Israeli figures.

The United States rushed military aid to support Israel, which has carried out a relentless campaign in Gaza that has killed at least 21,672 people, also mostly civilians, according to the Hamas-run territory's health ministry.

Those deaths have sparked widespread anger in the Middle East and provided an impetus for attacks by armed groups across the region that are opposed to Israel.

US forces in Iraq and Syria have also repeatedly come under fire from drone and rocket attacks that Washington says are being carried out by Iran-backed armed groups.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)