COLOMBO, Sri Lanka - Sri Lankan soldiers assailed the last slice of land still controlled by ethnic Tamil separatists, killing at least 32 rebels, the defense ministry said Saturday.

The military has driven the Tamil Tigers from nearly all their northern strongholds in an all-out offensive aimed at ending the South Asian island's quarter-century civil war.

Up to 200,000 civilians are cornered along with the holdouts in a strip of jungle and beach along the northeastern coast measuring just 50 square kilometres.

A Ministry of Defense statement said troops and rebels fought several battles in Mullaitivu on Friday, and at least 32 guerrillas died and more than a dozen were wounded.

The rebel force was making "desperate efforts to prolong its imminent defeat" including setting up artillery positions in a government-declared safe zone, it said.

Still, army spokesman Brig. Udaya Nanayakkara said troops recovered seven rebel bodies near one of the last rebel-held villages and that he could not immediately confirm the higher toll released by the ministry.

Rebel officials could not be reached for comment Saturday and battlefield details can't be verified independently because journalists are barred from the war zone.

Concern is mounting for the fate of the civilians caught up in the fighting.

The government has rejected calls from international aid groups for a cease-fire, saying it is on the verge of victory, while the rebels have ruled out any mass evacuation of civilians -- fueling suspicion that they are using them as a human shield.

The UN says thousands of innocents have been killed or wounded in recent fighting and the survivors are dangerously short of food, drinking water and medical supplies.

The top government health official in the rebel pocket told The Associated Press on Thursday that 13 people -- most of them elderly -- had died from starvation in the previous week.

However, the Sri Lankan government said in a statement Saturday that the exact cause of death was unknown because none of the 13 bodies had undergone a post-mortem examination.

It said the government had taken "all possible measures" to provide food and medicines to civilians in the rebel pocket, but gave no specifics.

Amnesty International said continued restrictions on the Sri Lankan media made it impossible to get an impartial picture of what was happening in the country.

The London-based rights group said at least 14 media workers have been killed in Sri Lanka since the beginning of 2006, while others were arbitrarily detained, tortured or have disappeared while in the custody of security forces.

"Without a free media able to express alternative views and offer the opportunity for public scrutiny, abuses can flourish under a veil of secrecy and denial," Yolanda Foster, Amnesty's Sri Lanka researcher, told a vigil in London to mark a prominent Sri Lankan journalist's first year in prison.

The Liberation Tigers of Tamil Eelam have fought since 1983 for an independent state for the Tamil minority, which suffered decades of marginalization at the hands of governments dominated by the Sinhalese majority. More than 70,000 people have been killed in the fighting.