An Afghan police commander and 13 junior officers have joined the Taliban in the western Afghan province of Farah, in what correspondents say could be the biggest defection by police.

They say the commander, named as Mirwais, was in charge of a 20-man checkpoint when he defected on Sunday.

The men are said to have taken heavy weaponry, radios and police vehicles including US-made armoured Humvees.

Farah is one of the most insecure areas in the relatively peaceful west. . .