3 UK citizens' terror talk causes flight to be grounded A backpack belonging to one of the men was destroyed by a controlled explosion.

 -- Three British men were detained in Germany late Saturday after allegedly having conversations involving terrorism on board a flight from Slovenia to London. The men were released Sunday, ABC News has learned.

Police in Cologne, Germany, where the flight was diverted, released a statement indicating that officers questioned the men -- aged 31, 38 and 48 -- and examined their cellphones, but did not find evidence that they were plotting a terror attack.

The incident, which took place on a flight by EasyJet, a low-cost British airline, reflects the level of concern about terror in Europe following the three ISIS-inspired attacks that have taken place in the United Kingdom since March.

“EasyJet can confirm that flight EZY3246 from Ljubljana to London Stansted diverted to Cologne on the 10 June," the airline said in a statement. "The captain took the decision as a precaution to enable the aircraft to go through additional security checks in Cologne where the aircraft was met by the police."

“We thank passengers for their understanding," EasyJet said in the statement. "The safety of easyJet's passengers and crew is our highest priority.”

The situation began when a female passenger overheard a conversation between the men on the flight Saturday, police said.

One of the men had a book with a picture of a sniper rifle on it, along with the word "kill," police said.

The plane was diverted to Cologne-Bonn airport as a precaution and the 151 passengers on board were disembarked using emergency slides, the Associated Press reported.

Police said that some passengers were injured while exiting the plane.

Authorities also carried out a "controlled explosion" on a backpack belonging to one of the men that contained wires, but these turned out to be part of a charging device, according to the AP.

The Associated Press contributed to this report.