The Centre on Monday asked the Assam government to tighten security across the state in view of the powerful explosion in Guwahati, which so far claimed seven lives.
A detailed report regarding the blast, which took place on the eve of Prime Minister Manmohan Singh's visit to Assam, has also been sought by the Centre.
Union Home Secretary Madhukar Gupta has spoken to Assam Chief Secretary P K Sarma and asked him to tighten security in Guwahati and other places, a Home Ministry spokesperson said.
Other senior officials of the Home Ministry were also in constant touch with the state government and assured all necessary assistance to find out the culprits involved in the explosion.
A bomb disposal and data collection team of the National Security Guard is also being sent by the Centre to Guwahati to assist the local authorities in the investigations.
Preliminary investigations indicated the hands of ULFA in the blast as the banned outfit carried out such explosion in the past prior to its 'Raising Day', which falls tomorrow, sources said.