Pakistan-based Khalistan separatists have stepped up efforts to revive militancy in Punjab by triggering a series of blasts in the state and in the national capital, the government said Wednesday.

The central and state security and intelligence agencies have taken measures and are maintaining extra vigil on the activities of the suspected Khalistani elements and their supporters,

Minister of State for Home Sriprakash Jaiswal said in Rajya Sabha. Investigations into the twin bomb blasts in cinema halls in Delhi last year, a minor bomb blast at ISBT, Chandigarh and the blasts in Jalandhar earlier this year revealed that pro-Khalistani elements are making attempts to revive militancy in Punjab, he said in a written reply.

"The central government remains in constant touch with the state government to monitor the situation," he said.