Bomb blast at school kills boy, 3, as fighting continues in Sri Lanka

A three-year-old boy was killed in a car bombing outside a school in the Sri Lankan capital, Colombo, as fighting continued between government forces and Tamil Tiger rebels.

The Tigers were immediately blamed for the bombing, which targeted a prominent politician from a party known for its opposition to their cause. In Muttur, the bodies of two more relief workers for a French NGO were found, bringing the number of its staff killed to 17.

The Sri Lankan government promised a full and independent investigation into the deaths of the aid workers, as several of their relatives accused its forces of responsibility.

There were initially fears of far higher casualties in the Colombo bomb, which exploded outside a girls' school in a residential area. But while the schoolchildren escaped serious injury, a three-year-old boy, who was nearby when the blast went off, was killed. The boy was waiting for his mother, who worked as a maid nearby, according to his 61-year-old grandfather, John Rathaya. "We were going home after work when it exploded," he said. "Why did they take my child? They could have taken me." Police said they believed a magnetic bomb had been attached to the back of a mini-van that exploded. It was clearly intended for the vehicle's passenger, S Sivathasan, a senior politician in the Eelam People's Democratic Party - a Tamil party which opposes the Tigers and is an ally of the Sri Lankan President Mahinda Rajapaksa.

Mr Sivathasan survived but his bodyguard was killed. Nine other people were admitted to hospital with serious burns. Two years ago, the Tigers tried to assassinate the party's leader, Douglas Devananda, in another bombing, but that also failed. The Liberation Tigers of Tamil Eelam (LTTE) have been fighting for a separate homeland for Sri Lanka's Tamils for more than two decades.

Reports from Muttur, which has been almost completely cut off from the outside world for several days, speak of bodies rotting in the streets. Both sides are preventing journalists from reaching the town.

The bodies of two more employees of the French NGO Action Contre la Faim (ACF) were found in a car in Muttur on Monday. The discovery comes after the bodies of 15 of the NGO's tsunami relief workers, who were found lying face down in its office in the town on Sunday. It appears the two found yesterday were trying to flee the killings in the office when they were murdered. It was being described as the worst single death toll of humanitarian workers since the bombing of the UN compound in Baghdad in 2003, which killed 24 including the head of the UN mission.

The government promised a full investigation as it came under increasing pressure over the killings. Both the government and the Tigers have accused each other of responsibility, and no one has yet come forward with definitive evidence of what happened.

But several of the victims' relatives accused government forces of the killings. And the Reuters news agency quoted one unnamed Western diplomat as saying: "All of our initial information suggests the government was involved."

The story of how the aid workers were trapped in the town as the fighting raged around them began to emerge yesterday. The fighting spread to Muttur unexpectedly last Wednesday. Government forces had launched a ground offensive on Tiger-held territory to the south, and there would have been concerns over rocket and shellfire. But no one expected fighting on the streets of the government-controlled town.

But the Tigers attacked Muttur in a surprise counter-offensive. As tens of thousands of the town's residents fled, the aid workers contacted ACF by telephone, asking to leave the town - but were told to stay, according to Sinathambi Navaratnarajah, the father-in-law of one of the victims. The NGO probably believed its staff would be protected by its humanitarian status - they were all wearing ACF T-shirts when they were found. It also had teams trying to break through into the town to get help to them from the south, but they could not get through.

Sixteen of the dead aid workers were Tamils, and one was a Muslim - but their ethnicity was no guarantee of safety from the Tigers, who have frequently targeted Tamils who do not support them.

The fighting was continuing last night, even after the Tigers claimed they had reopened the water supply whose closure the government said was the sole reason for its ground offensive. The government has said it will continue its operations until all Tiger forces are expelled from the area.