"A nearby vessel reported an explosion in the proximity of the Barbados-flagged, publicly US-owned, bulk carrier," Ambrey said, cautioning other ships to steer clear of the bulker which matches the "targeting profile" of Yemen's Houthi rebels.

The Houthis started targeting Israel-linked ships in the Gulf of Aden and the Red Sea in November, to pressure Israel to halt its brutal war and siege of Gaza.

They have also vowed to strike British and American ships after the US and Britain launched repeated strikes on Yemen in response to the ship attacks.

Before the latest reported attack, Ambrey said the bulk carrier was "hailed by an entity declaring itself to be the 'Yemeni Navy'," a title adopted by the Houthi rebels.

British maritime security agency UKMTO also reported an "attack" southwest of Aden, without elaborating.

The Houthi offensive has caused several major shipping firms to suspend passage through the Red Sea, which usually carries around 12 percent of global trade.

At least "15 commercial ships have been impacted" since November, including four US ships, US department of defence spokesman Pete Nguyen said on Friday.

On Tuesday, American forces shot down three drones and a missile fired toward a destroyer in the Red Sea, the US military said, after Yemen's Houthis announced they had targeted two of Washington's warships.

Houthi military spokesman Yahya Saree said earlier in the day on social media that their forces "will not stop until the aggression stops and the siege imposed on the Palestinian people in the Gaza Strip is lifted."