The Rajasthan government on Friday constituted a Special Investigating Team to probe the terror attack on Khwaja Mohiuddin Chisti's dargah at Ajmer which had killed three persons and injured many more on Thursday.

Union Home Secretary Madhukar Gupta said that the SIT will interact with central security agencies to find out which organisation had masterminded Thursday's blast. The blast had aimed at disturbing the communal harmony in the city, Gupta said.

Referring to the unexploded bomb recovered from the blast site on Friday, Gupta said, "We are analysing the explosive material and assembling of the bomb. That would lead to more details and agencies concerned are looking into this aspect," he said.

To a question regarding terrorist involvement in the incident, Gupta said, "their hand is quite visible."

The Home Secretary said the state authorities had been asked to work out a detailed plan to strengthen security arrangements in and around the Dargah, which is frequented by thousands of pilgrims from all religious sects.

A team from the elite National Security Guard was also examining the blast site.

In the wake of the blast, the Union Home Ministry issued a general alert throughout the country to maintain tight vigil ahead of major festivals like Eid-ul-Fitr, Dusshera and Deepwali.