Parts of Frankfurt Airport have been evacuated and boarding has been halted because there was "at least one unauthorized person in the security zone," a spokesman for Germany's federal police said on Tuesday.
Spokesman Reza Ahmari said that controls were being carried out on all people in the security zone and that boarding would resume thereafter.
The public was alerted to the measure an hour earlier when police said on Twitter that a police operation was ongoing "in area A of Terminal 1 at the #Frankfurt #airport ... this includes an immediate boarding stop and clearing the security area in levels 2 and 3."
Frankfurt Airport is Germany's busiest, with 64.5 million passengers counted in 2017.
Last month, police cleared and closed Terminal 2 and its satellite terminal at Munich airport after a 40-year-old woman slipped past security without being screened by personnel.
Nearly 330 flights were cancelled due to the incident, with over 32,000 passengers affected.
