Bomb defusal experts in the Sri Lankan capital, Colombo, have made safe a powerful explosive device found close to an area where many senior policeman live.

The discovery comes a day after the interception of a letter bomb addressed to President Chandrika Kumaratunga.

Police said the bomb was packed with ball bearings and was intended to cause massive casualties.

The BBC correspondent in Colombo says the Sri Lankan security forces have been on high alert since a suicide bomb attack last month at an election rally in which over twenty people were killed and President Kumaratunga injured. She says responsibility for the bomb is certain to be blamed on Tamil Tiger rebels fighting for an independent homeland.

Meanwhile, the Sri Lankan military say four Tamil Tiger rebels have been killed in fighting in the north of the country.

From the newsroom of the BBC World Service