Moscow/Kiev - A Russian Boeing 737 landed with its landing gear up on Thursday, suffering substantial damage but leaving passengers and crew unharmed.

The aircraft operated by the Russian airline KD Avia made the landing at the main airport of the Baltic port city Kaliningrad after a uneventful flight from Barcelona, Spain.

The plane's flight crew determined the landing gear had not extended while preparing to land at Kaliningrad, and flew around to make a second approach after determining "the flaps are working," the Interfax news agency reported.

The Boeing landed on its fuselage and engines on the Kaliningrad airport main runway. There was no fire and flight crew and 138 passengers evacuated the aircraft without injuries.

Emergency vehicles responded to the scene. Kaliningrad airport was reportedly still closed as of midday Thursday.

Transport authorities were investigating the incident. (dpa)