Houthi rebels claimed to have struck a British-registered oil tanker with a missile, setting it on fire.
The movement said they had targeted the Marlin Luanda on Friday evening.
The UK Maritime Trade Operations (UKMTO) said that the incident happened 60 nautical miles south-east of Aden.
US officials say a nearby naval ship is responding to the vessel’s distress signal and no injuries have been reported.
It is the latest attack on commercial shipping by the Houthis in and around the Red Sea.
UKMTO said authorities had been informed and were responding to the latest strike, and warned other vessels to transit with caution and report any suspicious activity.
Houthi military spokesman Yaha Sarea said the group used “a number of appropriate naval missiles” and Friday’s strike was “direct”.
Since November, the Houthis have launched dozens of attacks on commercial vessels travelling through the Red Sea, one of the world’s busiest shipping lanes.
A second wave of UK and US air strikes were carried out on Houthi targets in Yemen earlier this week.
The UK and US are also targeting the Iran-backed militant group with sanctions to cut of its financial resources.
