Firefighters are battling a blaze on a ship at Lisahally Docks this morning.
It is believed over 50 firefighters are dealing with the blaze, which began in one of the cabins on board the vessel.
The alert was raised at 7am this morning, Tuesday.
Fire crews from Londonderry have been joined by specialist teams from Belfast, who are working in partnership to bring the blaze under control in conjunction with the Port Authority.
The identity of the ship has not been disclosed and members of the public are asked to avoid the area.