Three people were killed and 11 injured when a powerful explosion rocked the mechanised three-wheelers parking area in front of Guwahati Railway Station in the heart of the city at around 5.15 pm on Thursday.

A man and his child were killed instantly and a woman succumbed to her injuries later in hospital. Police officials said they believed the outlawed United Liberation Front of Asom was behind the attack.

The bomb, hidden in a cycle-rickshaw, was detonated with a timer device in the parking lot, Senior Superintendent of Police Nitul Gogoi said.

The cycle-rickshaw, left by an unidentified person in the parking lot adjacent to an army and Border Security Force transit camp, was ripped apart by the blast that damaged an autorickshaw and several other vehicles.

The area is usually under tight vigil because of presence of the largest army transit camp, the BSF transit camp, the railway reservation counter, the railway station and the Reserve Bank of India [Get Quote] office in the same locality.

A tight vigil is usually kept by the railway police and the army. Top police officials rushed to the spot immediately after the blast. The area has been cordoned off even as the police launched a manhunt within the city.

The injured were immediately shifted to the nearest government civil hospital as well to Guwahati Medical College Hospital.

Earlier in the day, Assam Chief Minister Tarun Gogoi made light of ULFA's demand for sovereignty saying that it was not going to help Assam.

Addressing an august gathering of scholars and distinguished personalities on the occasion of unveiling of Asian Dialogue Society's report 'Shared Integration', a part of the society's greater Asia initiative, Gogoi asked, "How will the ULFA's demand for sovereignty help Assam?"

"Sovereignty wouldn't help Assam as it cannot grow and prosper in isolation. Assam can prosper only through integration with the rest of India as well as its Asian neighbours," Gogoi said.

Meanwhile, a visiting official delegation of neighbouring Bhutan, during a meeting with the chief minister, assured Assam government that the royal government of Bhutan wouldn't allow banned ULFA militants to set up fresh camps inside the Himalayan kingdom.

The Royal Bhutan Army had evicted the general headquarters of ULFA and camps of other north-east militant groups in an operation codenamed 'All Clear' in December, 2003.

With PTI Inputs