BERLIN (AP) — Police say a judge has ordered the continued detention of a young Polish man who forced open a locked perimeter gate at Germany's Hannover Airport and drove his car onto the airfield.

The 21-year-old suspect's motive remained unclear on Sunday, but police said they still had no indication his alleged actions were terror-related.

Authorities say he was apparently under the influence of drugs during Saturday's incident. At the airport, officers pursued him until he stopped the car underneath an airliner with 172 passengers on board.

The judge ordered him kept in custody pending possible formal charges. He is being investigated on suspicion of dangerous interference in air traffic, resisting police and driving under the influence of drugs.

A statement from police says he was previously known for narcotics violations.