Security forces in Sri Lanka have defused a bomb on a railway line, which they say was primed to explode when an express train passed by.

The device was discovered in the Badulla district by people living near the railway track.

The Sri Lankan government has blamed Tamil Tiger separatists for a recent spate of attacks on civilian targets.

On Tuesday, three people were killed when bombs exploded on buses in Colombo.

From the newsroom of the BBC World Service