Police and intelligence agencies have gone on an alert after a letter threatening to blow up several railway stations and religious places in Uttarakhand, including the Himalayan temples of Kedarnath and Badrinath, was received at the Haridwar railway station.

The letter, sent by ordinary post, was received by the Haridwar railway station superintendent on October 10, Additional Superintendent of Police, Government Railway Police (GRP), Aruna Bharti said on Sunday.