NAIROBI (Reuters) - The United Kingdom Maritime Trade Operations (UKMTO) agency said on Thursday that it had received a report of a merchant vessel being boarded 420 nautical miles southeast of Merca, Somalia.

UKMTO said in a statement that an unknown number of unauthorised people from two small craft were reported to have boarded the vessel.

Between 2008 and 2018, Somali pirates caused havoc in the waters off the country's long coastline. They had been dormant until late last year when pirate activity started to pick up again.

(Reporting by George Obulutsa; Editing by Alexander Winning)