Siliguri, Jan. 4: An anonymous threat written in Bengali on a sealed envelope has prompted the Bagdogra airport authorities to tighten security reports our correspondent.

The envelope was handed over to an air force security guard by a motorcycle-borne man, said K.K. Bhowmik, the airport director. “The guard handed it over to our gate supervisor who rushed to my quarters yesterday morning after he read saath diner moddhe airport attack hote pare (the airport could be attacked in seven days) on the envelope.”

Since there was no threat mentioned in the letter inside, the words on the envelope had been written mainly to draw attention, Bhowmik said.