Tamil Tiger rebels in Sri Lanka have released one of seven government soldiers they detained last week.

Scandinavian officials monitoring a ceasefire agreement asked the rebels to release the hostage on humanitarian grounds.

The rebels say they want to exchange their other prisoners for two Tamil Tigers held by the government.

On Tuesday, a delegation from the Sri Lanka peace monitoring mission went to Trincomalee for talks with security officials and members of the Tiger's political wing, in a bid to end the standoff.

The monitors have expressed concern that the incident could threaten the ceasefire agreement signed between the Sri Lankan authorities and the Tamil Tigers in February.

From the newsroom of the BBC World Service