A Northwest Airlines (search) DC-9 that had reported hydraulic problems collided with another aircraft Tuesday on the ground at Minneapolis-St. Paul International Airport (search), injuring six people, officials said.

The six were taken to the hospital, but the extent of their injuries was not immediately known, said Pat Hogan, spokesman for the Metropolitan Airports Commission (search).

Northwest released a statement saying several crew members were injured, but that no passengers were hurt.

Hogan said the DC-9 (search) had flown in from Columbus, 9 appeared to be partially lodged underneath the Airbus. The top of the DC-9's cockpit area had clipped the Airbus' wing and was damaged.

Hogan said the National Transportation Safety Board (search) was investigating.