Germany said yesterday it was tightening security at airports and train stations after receiving concrete evidence of planned terrorist attacks in the country, including one this month.

“From today, there will be a visible police presence. I thought it should be explained to citizens,” Interior Minister Thomas De Maiziere told a hastily called press conference in Berlin.

“There will also be a variety of measures that will not be visible. There is reason for concern, but no reason for hysteria,” he added. “According to information from a foreign partner which came to us after the Yemen incident, we suspect a planned attack is due to be put into action at the end of November,” Mr De Maiziere said. Last month authorities discovered two US-bound parcel bombs originating from Yemen, one of which went through Cologne airport in western Germany.

Citing security sources, the Tagesspiegel daily said the United States had tipped off Berlin that between two and four Al-Qaeda operatives were on their way to Germany and Britain to attempt attacks.