The Sri Lankan military denied on Thursday that it had shelled a "no-fire" safe zone in the north, the latest in a series of contradictory accounts of the conflict in the South Asian nation.

The pro-rebel TamilNet.com website said 129 civilians were killed and 282 wounded after army artillery shells landed in a tiny safe zone in the northeast measuring just 20 square kilometres.

Many Liberation Tigers of Tamil Eelam (LTTE) fighters have been pushed into the safe zone after government troops, as part of a massive military campaign, captured vast swaths of rebel territory in recent months.

TamilNet claimed shells landed in a child-care centre in the Pokka'nai region where people were lining up to receive humanitarian aid.

Military spokesman Brig. Udaya Nanayakkara called the report a fabrication fashioned to attract international attention and "mount pressure to have a ceasefire that will help the Tiger leadership to escape the army.

"We have not fired into the 'no-fire' zone."

But there were other accounts of shelling in the safe zone set up by the government in January to protect civilians.

The BBC quoted a health official as saying 60 civilians were killed after two medical centres in the safe zone were hit by shells on Wednesday, while the International Red Cross Committee said one of its aid workers had been killed the same day by shelling in the region.

The LTTE has not commented on any of the alleged attacks.

Independent journalists barred

None of these frontline accounts can be verified because the government bars independent journalists from the war zone. Both the military and the rebels have accused the other of carrying out war crimes, and the United Nations has said both sides may be guilty.

The fate of the civilians trapped there has become a matter of international concern, with the UN and aid groups warning of a bloodbath if all-out fighting breaks out there.

The government and aid groups accuse the rebels of using the civilians as human shields, and have called for them to be allowed to go.

The UN has said 2,800 civilians caught in the fighting have been killed and 7,000 more wounded since late January, though the government disputes that figure.

The UN estimates at least 150,000 civilians are trapped. The government says the number is more likely between 50,000 and 60,000.

The Tamil Tigers have fought since 1983 to create a separate state for minority Tamils, who have suffered decades of marginalization at the hands of governments controlled by the Sinhalese majority.

More than 70,000 people have been killed in the civil war.

With files from the Associated Press