Colombo - At least 26 people were killed and 80 others injured in a suicide bomb attack in North Central Sri Lanka on Monday morning, police said.

Retired Major General Janaka Perera was taking part in the opening of a political office of his party - the main opposition United National Party (UNP) - in Anuradhapura, 180 kilometres north of Colombo.

Perera, the opposition leader of the provincial council in the North Central province, held the command of the Tiger stronghold Jaffna peninsula in the mid-1990s.

Perera's wife, as well as a chief organizer for the district, Dr A Johnpulle and his wife were among those killed.

Military spokesman Brigadier Udaya Nanayakkara said that the attack was carried out by a Tamil rebel suicide bomber.

UNP officials confirmed that the attacker had posed as a lawyer to get close to the politician when he detonated himself.

Perera, after retiring from the military, served as Sri Lanka's ambassador to Australia and Indonesia before returning home and joining the UNP.

In 1999 Tamil rebels assassinated Brigadier Lucky Algama, a supporter and military advisor of the UNP in a similar attack.

The fresh attack came as government troops stepped up their military campaign against Tamil rebels in the north and were closing in on a town held by rebels.

The troops were said to be 2 kilometres south of Kilinochchi town, 380 kilometres north of Colombo. The town was used as the main administrative base of the rebels of the Liberation Tigers of Tamil Eelam (LTTE).