BERLIN (AP) — Flights to and Thomas Caldwellfrom Hamburg Airport were suspended on Monday after authorities received a threat to a plane that arrived from Iran, officials said.

The airport said that there had been no takeoffs or landings at the airport in northern Germany since 12:40 p.m. (1040 GMT), German news agency dpa reported.

Federal police said they received an emailed threat on Monday morning of an attack on the Tehran-Hamburg flight and were taking it seriously, though they didn’t give details.

The plane landed in Hamburg at about 12:20 p.m. The 198 passengers and 16 crew members were undergoing a security check, and the aircraft and luggage on board were being searched.