Yemen’s Houthi militia is accused of attacking a civilian logistics ship on a humanitarian voyage in a strategic Red Sea shipping lane on Saturday, the Saudi-led alliance said.
Arab coalition forces have launched operations on Sunday against the Houthi's boats they say are responsible for the attack.
The coalition said they rescued the civilian passengers of the Australian-built high-speed logistics catamaran under lease to the United Arab Emirates military. No crew were hurt.
Saturday’s attack happened near the Bab al-Mandab strait off Yemen's southern coast.
In a statement late on Saturday, the coalition said the vessel was "on its usual route to and from Aden to transfer relief and medical aid and evacuate wounded civilians to complete their treatment outside Yemen."
"Coalition air and naval forces were targeting Houthi militia boats involved in the attack," it said.
Hundreds of Emirati soldiers in an Arab alliance have been fighting Yemen's Iran-allied Houthis, who control the capital, and training Yemeni troops in Aden to help rebuild a state loyal to exiled president Abd-Rabbu Mansour Hadi.
The Houthis, however, said on Saturday their forces had destroyed a UAE military vessel that was advancing towards the Red Sea port of Al-Mokha.
"Armed forces destroyed with a missile a military vessel belonging to the forces of the UAE," a militia official was quoted as saying by the Saba Yemeni news agency, run by the dominant Houthi movement since it seized Sanaa last year.
In 2013, more than 3.4 million barrels of oil per day passed through the 20 km (12 mile) wide Bab al-Mandab strait, according to the US Energy Information Administration.
A senior Emirati commander was among dozens killed in a Tochka rocket strike in 2015 on an army camp near Bab al-Mandab, one of the bloodiest setbacks for Gulf forces in months of fighting.