Sri Lankan troops have captured four Tamil Tiger bases and inflicted heavy casualties in the northeast of the country.
Ground troops backed by artillery advanced overnight on rebel-held territory in the district of Trincomalee, forcing the withdrawal of 150 Tamil militants.
The Sri Lankan government has publicly said that it wants to clear the entire eastern province of Tamil Tiger rebels, and Thoppigala is thought to be the last rebel bastion.
In a separate incident in the eastern district of Batticaloa, suspected militants ambushed an armoured personnel carrier with a roadside bomb, killing three Sri Lankan soldiers and wounding 13.
The violence follows months of land and sea battles that have left over 4,000 people dead in the past 15 months.
It is estimated that 68,000 people have been killed since the civil war began in 1983.
