Guwahati, Dec 14: The Blast Investigation Operation team of the National Security Guard (NSG) will arrive here today to assist in the investigation of the Rajdhani Express blast.

The team will look for ballistic and forensic clues at the site of the incident, a spokesperson of the Home Ministry, which is closely monitoring the situation.

Condemning the blast, Union Home Minister Shivraj Patil has said, "I convey my sympathies to those killed and pray for speedy recovery of those injured in the incident. "

"People of our country understand the designs of terrorists and will not be cowed down by such incidents. The State Governments and Railways will take necessary steps to provide protection to passengers and see that such incidents do not recur, " he added.

Union Home Secretary Madhukar Gupta had also spoken to the Assam Chief Secretary. The latter has briefed Gupta about the steps taken in the wake of the blast.

Army and security forces have intensified operations against militants in the Upper Assam districts after the blast.

Security measures on the railway tracks have also been beefed up across the State.

At least five persons were dead and four others injured when a bomb exploded in the 2423 A Guwahati-Delhi Rajdhani Express in Assam on Thursday morning.

The explosion took place between Naojan and Chungajan in Assam's Golaghat District at around 1.00 a. m.

This is the first bomb blast on the Dibrugarh-New Delhi Rajdhani, although the train has been targeted once before in June 2006. (ANI)