Ambala (Haryana): A letter sent to authorities threatened to blow up the air force base in India's Harayana state, police said. The base in Ambala is where the newly acquired Rafale warplanes are stationed.
As a precaution security has been beefed up at the Ambala station, according to police.
The letter named the mastermind behind the operation as Rajesh Vaishya, a resident of Jalandhar. "The operation has been planned by 15 people - three of them ex-army men and top police officials", the letter said.