Story highlights "There was no real situation of danger," Cologne police say

151 passengers were evacuated via emergency slides; some suffered minor injuries

London (CNN) An easyJet flight headed to London made an emergency landing in Germany after three men allegedly had a "terrorism-related" conversation, police said.

But the three men -- all British citizens -- were released after witness testimony about the conversation could not be verified, said police in Cologne, Germany.

The plane traveling from Ljubljana, Slovenia, to London was diverted to the western Germany city of Cologne on Saturday.

The men, ages 31, 38 and 48, were initially arrested for a possible "crime against the state," police and prosecutors said in a joint statement Sunday.

Passengers alerted the flight crew because the men were "talking about terrorism-related content," Cologne police said.

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