An EasyJet flight made an unscheduled landing in Germany with passengers evacuating from emergency slides and flights suspended from Cologne-Bonn airport, after a pilot was informed of “suspicious conversation,” according to a spokesman for the airport.

Three male passengers were detained on Saturday evening in Cologne, Germany after their easyJet flight from Ljubljana, Slovenia to London made an unscheduled landing there, Cologne police said in a statement.

The aircraft landed in Cologne after passengers reported that the men were talking about “terrorist matters,” according to the statement. The men were not identified.

Police carried out security checks of the aircraft and questioned passengers after all 151 passengers were evacuated safely from the Airbus 319 aircraft using emergency slides, the airport said in a statement on its website.

Six aircraft were diverted to other airports as a result of the police investigation, the airport said. It said air traffic was affected for several hours as a result of the incident.

Federal police seized a backpack that belonged to one of the men, and exploded it outside of the aircraft, police said. They gave no information on the contents of the backpack and said officials continued to investigate the backpack.

The men continued to be questioned late Saturday evening. Other passengers were also being questioned, police said.

Bild newspaper quoted a spokesman for the German federal police as saying the pilot decided to land the aircraft in Cologne after passengers told airline personnel they had heard the men using words including “bomb” and “explosive.”

No comment was immediately available from federal police.