NAIROBI - An unknown group of people who boarded a merchant ship 420 nautical miles southeast of Merca, Somalia, have departed and the vessel's crew are safe, the United Kingdom Maritime Trade Operations (UKMTO) agency said on Friday.

UKMTO did not name the ship, but the European Union's anti-piracy force in the Indian Ocean and Red Sea, Operation Atalanta, said a Liberian-flagged merchant vessel Basilisk was boarded by suspected pirates in a similar location on Thursday.

Operation Atalanta sent one of its nearby warships to respond, the EU said.

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

  - Reuters