The Civil Aviation Department said the plane landed safely and no one was hurt. Police said it was not carrying passengers.

Flight UA2831, scheduled to depart at 10.30 am, took off at 10.47 am for Guam, the United States, but turned back and made an emergency landing due to a suspected engine problem. A video on Facebook showed flames shooting out of the aircraft's right engine while it was in flight. It is understood a bird hit the engine.

The tracker Flightradar24 said the plane kept circling off Lamma in a safety maneuver believed to involve the release of fuel.

Upon receiving the pilot's report, the department informed the airport fire contingent and Airport Authority to stand by and arrange for the aircraft to land.

The department said there was no report of injuries during the incident and the department will follow up on the incident with United Airlines.

The Airport Authority said it received a report at about 11 am that the plane needed to return to the city.

The plane landed safely and airport operations were not affected.

The Fire Services Department said 34 fire engines, seven ambulances and seven fire boats were deployed following the report of engine problems from the flight.

Police said that they received a report at 11.07 am that the plane had to urgently return to the airport because of engine problems.

"The aircraft was carrying goods and clothes with no dangerous items or passengers on board," said the police.