The UAE's first public condemnation of the hijacking comes 10 days after Houthi rebels captured the Rwabee with 11 crew on board in the Red Sea.

The Iran-backed insurgents say the ship was carrying military hardware but the Saudi-led coalition fighting in support of the Yemeni government insists it was medical equipment.

"We condemn, in the strongest terms, the Huthi act of piracy against the civilian cargo vessel Rwabee off the port of Hodeida," Lana Nusseibeh, the UAE's permanent representative to the United Nations, told the Security Council.

"This is a dangerous escalation against the safety of maritime navigation in the Red Sea. It requires the adoption of a firm position by the Security Council," she said, according to a foreign ministry statement.

The vessel's seizure has raised fears the seven-year war could spill over into the busy Red Sea shipping lane, a vital conduit for Gulf oil and cargo.

It prompted a coalition threat to bomb rebel-held ports including Hodeida, a lifeline for the shattered country where millions are teetering on the brink of famine.

Hans Grundberg, the UN's special envoy for Yemen, also said violence was escalating with clashes in Marib and Shabwa provinces, air strikes in Sanaa and Taez and fighting near Hodeida, as well as increasing drone and missile attacks on Saudi Arabia.

"We appear to once more be entering an escalatory cycle with predictable devastating implications for civilians and for the immediate prospects of peace," the Swedish diplomat told the Security Council.

"I am worried that battles could intensify along other fronts."

Yemen's civil war began in 2014 when the Houthis seized Sanaa, prompting Saudi-led forces to intervene to prop up the government the following year.

The UN has estimated the war killed 377,000 people by the end of 2021, both directly and indirectly through hunger and disease.