ALTADENA (CBSLA.com) — Two Pasadena Police choppers are damaged and six people reportedly injured after the two craft collided Saturday in Altadena.

Early reports indicate the injuries are minor. It is not known if the accident is weather-related.

The accident occurred at the Pasadena Police Department’s heliport just before 4 p.m.

The victims — five officers and one civilian observer — were all transported to the hospital where they are being evaluated.

Several of the injured were taken to Huntington Memorial Hospital, according to CBS2 and KCAL9 reporter Art Barron.

The cause of the accident is under investigation by the National Transportation Safety Board.

Barron reported the choppers — both OH-58′s — were badly damaged. “One ended up without rotor blades, the other with a damaged tail section.”

Pasadena Police Spokesperson Phlunte Riddle said it was believed the rotor blades of both helicopters touched during a maneuver.

Barron also spoke to Christina Garcia, who lives across from the heliport, and she recalled hearing “a loud explosion.”

Barron also reported that the Pasadena Police have a fleet of six helicopters so four will remain in commission.