RIYADH: Yemen’s seven-year war lurched into its latest crisis Monday with Huthi rebels saying they have seized an Emirati-flagged military ship which the Saudi-led coalition insisted was carrying medical supplies.

The Iran-backed Huthis released images of what they said were military jeeps and weapons on board the vessel, named Rwabee, which was captured in the Red Sea off the Yemen coast.

The coalition branded the hijacking an act of piracy and threatened to seize the ship back by force. The Rwabee was returning from a mission to set up a field hospital on Yemen’s Socotra island, it said.

“The militia must promptly release the ship, or the coalition forces will undertake all necessary measures and procedures to handle this violation, including the use of force if necessary,” coalition spokesman Turki al-Malki said.

But the rebels, who said the multinational crew was still on board, warned there would be consequences if the ship was targeted.

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The incident follows intensified fighting in recent weeks including multiplying Saudi airstrikes on rebel territory, while the Huthis have ramped up missile and drone assaults on the neighbouring kingdom.

The coalition has been fighting for nearly seven years in support of Yemen’s government against the Huthis, in a conflict that has displaced millions and created the world’s worst humanitarian crisis, according to the United Nations.

There was no immediate comment from the United Arab Emirates.

A US official based in the region said it appeared to be the first ship hijacking by the Huthis since they seized three in late 2019.

“The seizure was unusual... It looks to be the first known case of the Huthis seizing a Saudi-led coalition vessel in more than two years,” the official said, on condition of anonymity.