Troops, supported by air force fighter planes, destroyed three Tiger mortar positions in the eastern district of Batticaloa, the ministry said in a statement.

"In the confrontation one soldier died and 15 were injured," it said, adding that over 30 rebel bodies were found in the area.

Troops also recovered a haul of arms and ammunition from the battle zone.

However, the Liberation Tigers of Tamil Eelam (LTTE) dismissed military claims and said they beat back an army ground offensive, placing their losses at seven cadres wounded during a five-hour battle.

"We successfully beat back the military offensive and suffered only seven cadres from our side wounded," Tiger military spokesman Rasiah Ilanthiriyan told AFP by telephone from his base in the island's north.

"We are not sure of the casualties on the government side," he added.

Earlier in the day, Tigers set off a powerful mine at a government office in northern Sri Lanka, killing two constables, police said.

The LTTE planted the claymore device on a motorcycle parked at the district secretariat in the town of Vavuniya, 260 kilometres (160 miles) north of Colombo, police said.

"An investigation is underway to find out how the motorcycle was taken into the car park of the building without being checked," a police official in Vavuniya said by telephone.

The attack came despite tight security in the region, where several similar bomb attacks have recently taken place against police and security forces.

Asailor was wounded Tuesday in a separate mine attack in the northwest of the island, police said.

More than 60,000 people have been killed in Sri Lanka's Tamil separatist conflict in the past 35 years.