Police say it is logical to blame the LTTE though investigations underway

At least 63 other people were injured in the attack on the Sri Lanka Transport Board (SLTB) bus.

Police spokesman Senior DIG NK Ilangakoon said that police have begun investigations.

It is too early to point the finger on anybody, he told BBC Sandeshaya, but having noticed past attacks by the LTTE on civilians it is logical to accuse the Tamil Tigers.

Women and children

Several bus attacks earlier this year were blamed on the LTTE.

Women and children are among the casualties, hospital authorities said.

As soon as the Kahapola bound bus turned to the road from the bus stand, I heard a loud explosion Eyewitness

Director of Kalubovila hospital Dr. R Gunawardane told BBC Sandeshaya that three women and a ten-year old boy were killed in the blast.

16 women are among the injured. Out of 63 injured, the condition of 12 people is serious, Dr. Gunawardane said.

Lakshman Surasinghe, a newspaper vendor in Piliyandala bus stand, told BBC Sandeshaya that glass shattered in his shop as the bomb exploded on the bus.

Eyewitness account

“As soon as the Kahapola bound bus turned to the road from the bus stand, I heard a loud explosion,” he said.

A fire erupted at the rear of the bus but it did not spread into the front part, he added.

Violence in Sri Lanka has intensified since January, when the government pulled out of a ceasefire agreement.

Earlier, the military said its troops had taken control of a church containing the country's most important Roman Catholic shrine.

The shrine lies on the front line in the town of Madhu in the northern Mannar region.

Both sides in the conflict have recently accused each other of shelling the revered complex, and photographs have shown considerable damage.