Sri Lankan troops and Tamil Tiger rebels have fought fierce battles in the north of the island with the loss of many lives, the two sides say.
Fighting is worsening - here rebel bodies are handed over in October
About 30 soldiers and rebels are reported to have died. Both sides say the other suffered heavy casualties. There is no independent confirmation.
Military jets also pounded a suspected rebel training base in the north-east.
Fighting between troops and the rebels, who want autonomy in the north and east, has worsened in recent months.
The military says at least 22 rebels were killed in fighting near Mannar in the north-west on Thursday. Two soldiers are said to have died.
According to the military, the bodies of eight rebel fighters were recovered after the fighting. Soldiers learnt of other rebel casualties from radio intercepts.
In a clash further north at Muhumale in the Jaffna peninsula, another eight rebels were killed and their bodies left behind on the battlefield, the army says.
The rebels, however, said they had killed at least 25 soldiers near Mannar, with the loss of seven of their own.
They said troops had suffered casualties in the fighting in Jaffna, while the rebels had not.
The pro-rebel TamilNet website said a young woman had been shot dead by troops while they were evacuating casualties from the battlefield near Mannar.
Quoting residents, TamilNet said the mother of two was killed when soldiers "opened fired at cows that were sleeping on their way, blocking the ambulances".
A Catholic priest confirmed the death of Surendini Imanuel, 33.
Speaking to the BBC Sinhala service from the mortuary at Mannar hospital, the priest could not say who had killed her. But he confirmed she had been shot dead in an army-controlled area.
At least 40 troops had been taken to hospital following the clashes, the AFP news agency said, quoting military sources.
According to the defence ministry, the rebel training camp in the north-eastern district of Mullaitivu had been "severely damaged".
There was no immediate response from the Tamil Tigers.
The latest clashes came after a Tamil Tiger attack on an Air Force base last week which left 14 security forces personnel dead and destroyed eight aircraft.
Observers say the two sides now seem to be gearing up for a major confrontation in the north of the country.
Despite losing territory in the east earlier this year, the rebels still control a vast swathe of land in the north.