Guwahati, May 26 (IANS): Despite a bomb blast in Tinsukia district hours ahead of her scheduled visit here, United Progressive Alliance (UPA) chairperson Sonia Gandhi decided to join the official celebrations of the first anniversary of the Assam government's third consecutive term.

Gandhi is likely to return to Delhi Saturday evening, according to officials.

The security agencies deployed in the state have drawn an elaborate security plan to foil any attempt by the anti-talks faction of the United Liberation Front of Asom (ULFA) militants to disrupt the function, an official added.

The banned organisation had earlier called a 12-hour shutdown across the state to oppose the UPA chairperson's visit to Assam.

According to police, a blast took place late Friday night at Philobari in Tinsukia district, over 500 km away from Guwahati, in which an unidentified person was killed.

The bomb was planted in front of the house of a Congress leader, police said.