Israeli troops have shot dead a 12-year-old Palestinian boy during a protest against Israel's barrier in the occupied West Bank, medics say.

The Israeli military said it was investigating what had happened.

It happened at Nilin village, west of Ramallah, where peace activists say Israel is taking 25 hectares of land from villagers to build the barrier.

The Israeli army is replacing the main access road to the village with a tunnel under military control.

Activists say the plan will have the effect of turning Nilin into a prison. Israel says the barrier and other construction work is necessary for security reasons.