A Boeing (BA) 787 Dreamliner's nose gear unexpectedly retracted while parked at a gate at Frankfurt airport, aircraft operator Lufthansa said.

Several crew members and ground staff who were on board the aircraft sustained injuries and are undergoing medical treatment, Lufthansa said Thursday in an emailed statement to MT Newswires.

The incident occurred before passengers had boarded the aircraft, which was scheduled to depart for Los Angeles as flight LH450, Lufthansa said.

"We are currently investigating the exact circumstances together with the relevant authorities," Lufthansa said.

Boeing and Frankfurt Airport did not immediately respond to requests for comment from MT Newswires.

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