US troops killed in Afghanistan

US-led forces in Afghanistan say three of their troops have been killed and another injured by a roadside bomb in the west of the country.

Separately, the coalition said 55 militants had been killed in a clash in Uruzgan province.

Earlier reports by Afghan officials said 35 militants had died there.

The coalition said more than 20 militants, including a Taleban commander, had died in other fighting in Uruzgan and Farah province.

There is no independent confirmation of the coalition claims.

The Nato-led forces said their troops had killed a motorcyclist they suspected was about to carry out a suicide attack in Helmand province.