Gunfire broke out off the coast of Yemen on Friday in an incident appearing to involve a private yacht with a glamorous Hollywood history.
Private guards on the yacht Kalizma fired at Yemeni coast guards after mistaking them for pirates, according to a maritime intelligence company.
The yacht once belonged to the actor Richard Burton, who gave it as a gift to his wife Elizabeth Taylor and while on board presented her with the 69-carat Taylor-Burton diamond.
It was not clear if anyone was wounded in Friday's gunfire.
The British military had initially reported a vessel under attack by three boats early on Friday.
But it later downgraded the attack to an incident after clarifying that the gunfire was "government agency activity".
Ambrey, a maritime intelligence company, said the Yemeni coast guard had approached a Cook Islands-flagged yacht after it failed to respond to radio calls.
According to the coast guard, “an armed security team ... on board the yacht then opened fire on the approaching Yemenis and attempted to escape perceived pirates”, the company said.
The coast guard “returned fire and followed the yacht for approximately an hour until communications with the yacht could be established and the misunderstanding between the parties resolved”.
Satellite tracking data appeared to show the Kalizma as the craft involved, the Associated Press reported, based on co-ordinates provided by the British military.
The Royal Navy's UK Maritime Trade Operations agency provides updates to merchant shipping on possible threats in the region.
Yemen's government did not publicly acknowledge the incident.
The Gulf of Aden is a busy route for global trade and has been the site of attacks attributed to Yemen’s Iranian-backed Houthi rebels as its civil war rages.
The gunfire occurred south of Nishtun, which is held by forces loyal to the internationally recognised Yemeni government.
The government is backed by a Saudi-led coalition in a war with the Houthi rebels who seized the capital Sanaa in 2014.
The attack came after Iran separately seized an oil tanker on Thursday carrying crude for Chevron on its way to Houston, Texas.
Earlier in the week, three Russians and two Egyptians were reported missing near Yemen's Red Sea coast, raising fears of piracy.
