At the Berlin capital airport BER on Sunday evening, federal police officers searched an unscheduled aircraft that landed in between.
At the remote parking position of the aircraft, there were numerous police cars with flashing lights, sniffer dogs searched the passengers' luggage placed on the apron.
The measures continued into the night, and there was no end in sight at first.
Why the Ryanair plane, which was on its way from Dublin in Ireland to Krakow in Poland, had to land in Berlin shortly after 8 p.m. was initially unclear.
For tactical reasons, a police spokeswoman initially did not want to give any further details.
The 160 passengers were brought to the terminal building and cared for there.
When they could start their onward journey was initially unclear - the airport lifted the night flight ban for the flight as a precaution.