Colombo  - International aid officials expressed concern Monday about artillery bombardments that hit a hospital in a Tamil rebel-controlled area in northern Sri Lanka and killed at least eight people.

UNICEF spokesman James Elder said the organization confirmed that the hospital in Pudukudirippu, 385 kilometres north-east of Colombo, had been shelled twice Sunday night.

He said the second attack had damaged a 30-bed pediatric ward that was overcrowded with children injured in the conflict between the government and separatist rebels. But he could not confirm the number of killed and injured.

However, Dr P Varathan at the Pudukudirrippu hospital said in a telephone interview that in the first artillery barrage, two people were killed and in the second attack six people were killed and more than 20 were injured.

The pro-rebel Tamilnet website blamed government security forces for firing at the hospital.

But a military spokesman in Colombo, Brigadier Udaya Nanayakkara, denied any government involvement in the attack, saying, "We have no reason to attack the hospital."

The International Committee of the Red Cross (ICRC), in a statement issued Sunday after the first attack on the hospital, expressed serious concern about the situation.

"We're shocked that the hospital was hit, and this for the second time in recent weeks," said Paul Castella, head of the committee's Colombo delegation. "The ICRC calls on both parties to respect their obligation to spare medical facilities and activities as required by international humanitarian law in all circumstances."

"Wounded and sick people, medical personnel and medical facilities are all protected by international humanitarian law," a Red Cross statement said without naming any party responsible for the attack. "Under no circumstance may they be directly attacked."

The statement said the hospital currently has more than 500 patients, some of whom were still waiting to be transferred to a government-controlled area for more adequate treatment.

"The ICRC has been supporting the hospital's staff by setting up a makeshift structure for triage, receiving ambulances and helping to clean the facility," its statement said. "It has also provided mattresses for patients who find themselves in the corridors because there is no longer any room in the wards."

Morven Murchison-Lochrie, a Red Cross medical coordinator working at the hospital, was quoted as saying, "The staff are under acute stress, surrounded as they are by the sound of the ongoing fighting and the influx of new patients."

"Ambulances are constantly arriving, but people are also being brought in by wagon, pickup truck, tractor and even motor scooter," Murchison-Lochrie said.

The fighting was expected to intensify in the next few days as security forces were set to capture the one-time rebel stronghold of Mullaitivu, which is now the last area held by the rebels.

Tamil rebels have been fighting for an independent homeland for minority Tamils in the north and eastern parts of majority-Sinhalese Sri Lanka for the past 26 years. The insurgency has claimed more than 76,000 lives and displaced tens of thousands of people.

The government has captured vast areas formerly held by the rebels in the northern and eastern parts of the country in their operations launched in August 2006 and has now entered what it described as the final phase of its offensive. (dpa)