Fire service spokesman Sven Gerling said his initial information was that two helicopters had crashed, but he had no further details on the accident.
Federal Police spokesman Frank Brochert confirmed there "was an incident during an exercise" and that emergency crews were on the scene. He had no details about the accident.
More top news
Heavy rain and wind for Scotland and northern parts this weekend with an amber weather warning issued and travel disruption expected.
Heavy rain continues to affect Western Scotland and Northern Ireland
A surgeon linked to two deaths and a series of botched surgeries is to return to work despite an ongoing investigation, ITV News understands