The United Kingdom Maritime Trade Operations (UKMTO) agency said on Friday it has received a report of an incident 45 nautical miles (83 kilometres) south of Yemen's Mokha.

The master of a ship reported an unmanned boat with a blue and white hull about half a nautical mile away at the location of the flagged incident.

"The boat was acting unpredictably before moving away from the area," UKMTO cited the ship's master as saying.

The ship and crew are safe, UKMTO said, adding that authorities were investigating the incident.