Colombo, Jan 2: At least four people were killed and many more injured when a bomb targeting a military bus in the Sri Lankan capital, Colombo, went off on Wednesday.

A Claymore landmine is said to have been used for the blast, police and military officials have said.

The powerful explosion took place near Hotel Nippon in Colombo's commercial Slave Island area.

The blast took place as the military bus was passing a busy junction that houses key military installations, reports said.

A foreign news agency quoted a hospital official as saying that two of those killed were soldiers.

Military officials said that they suspected the separatist Tamil Tigers to be behind the incident. However, the LTTE, denied their involvement in the blasts.

Victims were taken to the Colombo national hospital, where several people were reportedly in critical condition.

A military official said there there were "about 11 soldiers" on board the bus.

Most of the victims were civilians while a few soldiers were also admitted with shrapnel injuries, Hospital Director Hector Weerasinghe said.

Police and eyewitnesses said that the low-budget Nippon hotel suffered extensive damage and staff members were also among those wounded.

Fighting between troops and the rebels, who want autonomy for minority Tamils in the north and east, has worsened in recent months.

At least 70,000 people have died since the war began in 1983. (ANI)