According to government figures, 139 separatists and seven soldiers have died since the start of the month.
However, both sides frequently make vastly different casualty claims and it is impossible to independently verify the death tolls.
"We captured one square kilometre," Brigadier Udaya Nanayakkara, military spokesman, said. "To gain ground advantage ... we are applying pressure. Whenever possible we will confront them."
The military has driven deep into Tamil Tiger territory in recent months and pushed the front lines back from three to 20km in different areas, Nanayakkara said.
De facto state
Senior military officials have vowed to dismantle this year the de facto state established by the group, who are fighting for an independent homeland for the country's Tamil minority.
Tens of thousands of people have died in the conflict which began in 1972.
Meanwhile, security was tightened for members of parliament after a cabinet minister and his bodyguard were killed by a bombing just outside the capital Colombo.
The number of bodyguards and security vehicles assigned to politicians was increased after Tuesday's attack on DM Dassanayake, Sri Lanka's nation building minister.
"The government has agreed to increase the security of MPs with immediate effect," WJM Lokubandara, parliament's speaker, said.