There have been fresh reports of civilian casualties as ferocious battles continue in Sri Lanka between soldiers and Tamil Tiger rebels.
A senior government heath official in rebel-held territory told the BBC at least 15 civilians had been killed in shell attacks in the past two days.
The military has strongly denied being responsible for the incident, in which more than 100 people were injured.
The Liberation Tigers of Tamil Eelam (LTTE) have not yet commented.
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 and coastal area in the Mullaitivu district.
It is estimated that between 70,000 and 200,000 civilians are caught up in the conflict in the north-east and aid agencies have expressed concern over their safety and security.
Recently, the International Committee of the Red Cross "warned of an impending humanitarian catastrophe unfolding in the Vanni region" in north-eastern Sri Lanka and called for a mass evacuation of civilians and for far more aid to be allowed in.
Meanwhile, a senior health official working inside Tamil Tiger-held areas in Mullaitivu district has told the BBC by telephone from a makeshift hospital in the war zone that "shells continue to fall inside government-designated safe zone and outside the area, causing civilian casualties".
The official, Dr T Varatharaja, said "at least 15 civilians were killed in the attacks in the past two days", adding that he believed the artillery fire came from an area dominated by security forces.
He also said there was a severe shortage of essential medicines required for surgery and food inside rebel-controlled territory.
Allegation denied
The military has strongly denied being responsible for the shelling. Sri Lankan military spokesman Brigadier Udaya Nanayakkara told the BBC the army had no need to fire at civilians and that it had stopped using heavy weapons in the current fighting.
"This health official is under pressure from the rebels to talk up civilian casualties. So, we cannot believe his version," Brigadier Udaya Nanayakkara said.
He in turn accused the rebels of firing from inside the safe zone for civilians.
Neither of these versions can be independently confirmed as journalists are not allowed to report from inside the conflict zone.
A recent statement from the Sri Lankan Health Ministry said that "the government has taken all possible measures to provide enough food and medicines to the people kept by the LTTE as human shield".
The United Nations has also accused the rebels of preventing the civilians from leaving the war zone, saying there were credible reports that Tamil Tigers were shooting at those who were attempting to flee the area.
The rebels deny the accusation that they were holding the civilians against their will and that they were firing at civilians.
Escalation
Earlier, the army said it had beaten back a series of rebel counter-attacks in the north-east, killing more than 100 rebels in recent days.
A military spokesman said they had recovered bodies of more than 50 rebels. He said the army too had suffered casualties but the number was comparatively very low.
The Tamil Tigers have not officially reacted to the military’s claims but pro-rebel websites said the rebels had thwarted the army’s offensive and killed more than 400 soldiers.
The two warring sides tend to exaggerate enemy casualties while downplaying their own.
The latest escalation in the fighting comes days after the UN said that thousands of civilians had been killed and wounded in the fighting in recent months.
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