The Sri Lankan military says it has overrun a strategically important Tamil Tiger defensive line in the north of the country.
Scores of fighters from the separatist Liberation Tigers of Tamil Eelam were killed in several days of heavy fighting in the Jaffna peninsula, the military said.
"They had a lot of casualties and we are going toward the second line of defense," Brigadier Udaya Nanayakkara, a Sri Lankan military spokesman, said.
The Tamil Tigers, who are fighting for an independent homeland in the north and east of the country, have two further defensive lines in the area around Muhamalai.
There was no immediate comment from the separatists, but most communication with the north of the island has been cut by a major military offensive launched after Colombo pulled out of a Norwegian-brokered truce with the Tamil Tigers in January.
The Sri Lankan military statement followed a report from the Tigers saying they had forced back a new push into their territory by government forces.
A website affiliated to the separatists had said on Wednesday that Tamil Tiger fighters had killed 36 soldiers along the defensive line.
The Sri Lankan defence ministry has reported a number of significant gains in recent weeks, including the towns of Mankulam, located just south of the LTTE's major stronghold of Kilinochchi, Kumalamunai, and Poonenyn on the western coast.
Tens of thousands of people have been killed since the LTTE began an armed struggle in 1972 to set up a separate region for minority Tamils.