The government says this image shows the bodies of rebels killed in fighting
Both the Sri Lankan army and sources supportive of Tamil Tiger rebels have reported a bloody escalation in the fighting in the country's north-east.
A military spokesman said it had killed about 100 rebels in a series of clashes since Friday.
Pro-rebel websites said rebels had thwarted a government offensive, killing more than 400 soldiers.
Neither claim can be independently confirmed, as journalists are barred from the war zone.
The Tigers have been driven from most of the territory they held by an army offensive over recent months, and are now cornered in a small patch of jungle in the Mullaitivu district.
Military officials say they are launching a final push against the rebels in the hope of bringing the entire area under government control by next month.
On Sunday, Brig Udaya Nanayakkara told the BBC that about 100 rebels had been killed as the army drove back rebel counterattacks.
He said more than 50 rebel bodies had been recovered.
Meanwhile, pro-Tiger websites claimed rebels had beaten back an army offensive, killing 400 soldiers in the process.
The pro-rebel website Tamilnet also claimed "indiscriminate shelling" by the army in camps for those displaced by the fighting had killed 208 civilians from Thursday until Saturday.
Despite suffering a series of defeats at the hands of government forces, the rebels have vowed to carry on fighting.
The government, meanwhile, has rejected calls for a temporary ceasefire to allow relief for the tens of thousands of civilians caught up in the conflict, saying it would only give the rebels time to regroup.
The latest escalation in the fighting comes days after the United Nations said that thousands of civilians had been killed and wounded.