The Saudi-led coalition battling Yemen's Houthi rebels says two crew members have been killed in an attack on one of its warships in the Red Sea.
A coalition statement said three Houthi "suicide boats" had approached a Saudi frigate west of Hudaydah on Monday.
One of the boats collided with the rear of the frigate and exploded, causing a fire, the statement added.
However, a rebel-controlled news agency cited a source as saying the warship had been hit by a guided missile.
The US-backed coalition has fought the rebels since March 2015, when they forced Yemen's internationally recognised President Abdrabbuh Mansour Hadi into exile.
More than 10,000 people have been killed and 40,000 wounded since then, according to the UN.
Warships have been deployed in the Red Sea and Gulf of Aden as part of what the coalition says is an operation to stop the Houthis receiving weapons from Iran, which backs the rebels but denies providing military support.
"A Saudi frigate came under a terrorist attack by three suicide boats belonging to the Houthi militias while on patrol west of the port of Hudaydah," the official Saudi Press Agency quoted the coalition statement as saying.
"The Saudi ship dealt with the boats as necessary. However, one of the boats collided with the rear of the vessel, resulting in the explosion of the boat and a fire at the rear of the ship. The crew extinguished the fire," it added.
"Two members of the ship crew fell as martyrs and three others were injured."
The Houthi-controlled Saba news agency cited a military source as confirming a warship had been targeted off western Yemen on Monday. But the source said the vessel had been hit by a guided missile as it tried to approach the coast.
"The targeting of this warship comes within the framework of the legal right of Yemen to defend the homeland and its sovereignty," the source added.
Coalition and pro-government forces are also currently attempting to advance up the west coast in an attempt to drive the rebels out of Hudaydah and other ports.
The coalition warned that the Houthis' use of Hudaydah "as a launching pad for terrorist operations is a serious development that would affect the international navigation and the flow of humanitarian and medical assistance into the port".
The coalition's naval blockade and the wider conflict have caused a humanitarian crisis in Yemen, leaving more than seven million people severely food insecure.