Imphal, January 15: The residence of the former chief minister Radhabinod Koijam, located at Thangmeiband, was attacked by unidentified armed persons last night in what appears to be an incident of election-related violence.

According to official sources, unidentified persons fired some 20 rounds at the gate of Radhabinod Koijam�s residence at around 9 pm last night and hurled a hand grenade inside the compound of the house.

While the grenade failed to explode, a scooter parked inside the compound near the gate was damaged in the gunfire.

The gunmen, who came on a Hero Honda motor cycle and a Kinetic Honda scooter fled after the Radhabinod�s house guards retaliated.

Police today recovered a Kinetic Honda scooter believed to have been used by the unknown attackers.

In another incident, this morning some unidentified persons locked up the office of the Manipur Pradesh Congress Committee, MPCCI, located at the Congress Bhavan on BT Road, after threatening the office staff.

According to Congress sources, two unidentified persons came to the Congress Bhavan this morning and asked to see the MPCCI president O Ibobi.

On being told that O Ibobi was in Delhi at the moment, the two persons declared that no one at the office would be allowed to work, and locked up the office.

The locks were broken and the Congress offices reopened with the help of the Imphal city police later today.

Party leaders have condemned the incident as an act of terrorism.

Reliable sources in the Congress said former chief minister Rishang Keishing and MPCCI president O Ibobi had recently been served noted by a hill based underground group for Rs 20 lakhs and Rs 5 lakhs respectively.