At least 15 people were killed and 40 injured on Saturday, when a powerful blast ripped through a private passenger bus at Seenigama on the Colombo-Galle coastal highway in South West Sri Lanka.
The blast which occurred at about 2.45 pm, was the second in a passenger bus in two days.
On Friday, there was a blast in a bus at Nittambuwa, on the Colombo-Kandy road, which killed six persons and wounded fifty others, ten of them critically.
The National Security Media centre said that the bus which was blasted on Saturday, was going from Colombo to Matara in the deep south of the island, beyond Galle.
The injured were rushed to the nearby Galle-Karapitiya hospitals.
Further details were not immediately available.
Seenigama, is no stranger to tragedy. It was here that the waves of the tsunami hit a passenger train and killed 4,000 people in a matter of a few minutes on December 26, 2004.
The government Defence Spokesman, Keheliya Rambukwella, blamed the LTTE for the Nittambuwa blast and said that the LTTE was indulging in terrorism because it was frustrated by a string of defeats on the war front.
The attacks on soft civilian targets by the LTTE are generally explained by the heavy civilian casualties, which the Sri Lankan Air Force has been inflicting in its recent raids in the Tamil-dominated North-East.
In Padahuthurai in Mannar district, 16 civilians, including small children, were killed in an aerial bombardment on Tuesday.
The Bishop of Mannar, Rev Royappu Joseph, had described the raid as a "crime against humanity."
He also said that there were no LTTE military installations in the vicinity.
Even in the air attack on Alampil in Mullaitivu district later in the week, the dead were civilians.
Following the air attacks, the LTTE had warned that it would retaliate in a telling manner.
The Sri Lankan Armed Forces, however, have maintained that the targets taken were invariably the LTTE's military installations, especially its Sea Tiger (naval) bases.
Only these installations were damaged, the forces said.
Commenting on the LTTE's selection of soft targets outside Colombo, a political observer said that the rebel group was doing so because penetrating the capital city of Colombo was getting difficult in view of the stepped up and very tight security there.