Nanayakkara said that the Tigers, who are listed by the US, EU, Canadian and Indian governments as a "terrorist" group, have in the past week have carried out two suicide attacks in an attempt to stop advancing troops.
In Puthukudiyiruppu, which is the last sizeable village believed to be held by the Tigers, 35 LTTE fighters in an armour-plated vehicle launched a suicide attack against government troops, Nanayakkara added.
"We believe all 35 were killed but we only recovered 11 bodies," he said.
Since January 1, around 17,900 have fled the fighting - roughly between seven and 15 per cent of the total number trapped in the area.
|Both sides deny targeting civilians in the ongoing conflict [AFP]
Aid agencies said around 250,000 were inside the conflict zone before the exodus began, while the government disputed the figures claiming there were only 120,000.
The defence ministry said that medical care, food and water was being provided at the frontlines for the fleeing civilians.
The government, aid agencies and rights groups have accused the rebels of forcibly keeping people in the war zone as human shields, conscripts and labourers, a charge the Tigers deny.
The separatists did not immediately confirm or deny the reports, but the pro-rebel website TamilNet said the military had shelled the A-35 highway and groups of civilians, killing more than 120 people on Friday and Saturday.
The International Committee of the Red Cross has said that hundreds of civilians have been killed in the fighting this year.
The military denies targeting civilians.
It is impossible to independently verify the two sides' claims as journalists are banned from the war zone.