A UK-owned ship attacked by Houthi militants has sunk in the Red Sea, the United States military says as it echoes a warning from Yemen's internationally recognised government that the vessel's cargo of hazardous fertiliser poses a risk to marine life.
The Belize-registered Rubymar is the first vessel lost since the Houthis began targeting commercial ships in November.
Those drone and missile assaults have forced shipping firms to divert vessels the long way around southern Africa, disrupting global trade by delaying deliveries and sending costs higher.
The sinking bulk carrier also "presents a sub-surface impact risk to other ships transiting the busy shipping lanes of the waterway", US Central Command (CENTCOM) said in a statement on social media platform X.
The Iran-aligned Houthis, who control the north of Yemen and other large centres, say their campaign is a show of solidarity with Palestinians in Gaza.
The Houthi attacks have prompted a series of strikes against their positions by the US and Britain, and have led other navies to send vessels to the region to try to protect the vital Suez Canal trade route.
The Rubymar went down in the southern Red Sea late on Friday or early on Saturday, according to statements from the Yemen government and CENTCOM.
The US military previously said the February 18 missile attack had significantly damaged the bulk vessel and caused a 29km oil slick.
The ship was carrying about 21,000 metric tons of fertiliser, CENTCOM said on Saturday.
"The sinking of the Rubymar is an environmental catastrophe that Yemen and the region have never experienced before," Ahmed Awad bin Mubarak, the foreign minister of Yemen's internationally recognised government in Aden, said in a post on X.
"It is a new tragedy for our country and our people.
"Every day we pay the price for the adventures of the Houthi militia ..."
The Houthi attacks have stoked fears that the Israel-Hamas war could spread, destabilising the wider Middle East.
Yemen's internationally recognised government, which is backed by Saudi Arabia, has been at war with the Houthis since 2014.
The release of such large amounts of fertiliser into the Red Sea poses a serious threat to marine life, said Ali Al-Sawalmih, director of the Marine Science Station at the University of Jordan.
The overload of nutrients can stimulate excessive growth of algae, using up so much oxygen that regular marine life cannot survive, said Al-Sawalmih, describing a process called eutrophication.
"An urgent plan should be adopted by countries of the Red Sea to establish monitoring agenda of the polluted areas in the Red Sea as well as adopt a clean-up strategy," he said.
The overall impact depends on how ocean currents deplete the fertiliser and how it is released from the stricken vessel, said Tony Wang, assistant professor at the Department of Earth and Environmental Sciences at Boston College Xingchen.
The ecosystem of the southern Red Sea features pristine coral reefs, coastal mangroves and diverse marine life.
