Colombo, January 2: At least four people, including a soldier, were killed and 24 others were injured when a powerful bomb targeting an army bus exploded in the heart of the Sri Lankan capital Wednesday morning.

The bus was badly damaged and 10 soldiers were among the injured.

The defence ministry immediately blamed the Tamil Tigers for the 9.30 a.m. explosion on a street in Slave Island, a commercial hub in central Colombo, just when the rush hour traffic was picking up. "Liberation Tigers of Tamil Eelam (LTTE) terrorists have carried out a cowardly bomb attack targeting an army bus carrying sick personnel," the ministry said in a statement.

The bomb had apparently been placed in the external unit of an air conditioning machine at Nippon Hotel, which a family of Indian origin owns. The blast site is at a tri-junction, with the Sri Lanka Army headquarters not far away.

Wednesday's blast was the second terror attack in Colombo in the first two days of 2008. On Tuesday, a Tamil MP, T. Maheswaran, was shot dead as he was worshipping in a Hindu temple at Kotehena, adjacent to the Colombo harbour. The alleged assailant was shot and wounded by Maheswaran's bodyguard and is being questioned by the police.

Government spokesman Keheliya Rambukwella Wednesday said that it was significant that the murder weapon was a kind of micro pistol typically used by LTTE hit squads.