Afghanistan’s president has ordered increased security for workers building roads, dams, electricity lines and telecommunications systems in an attempt to revive key projects stalled by insurgent attacks that have killed or kidnapped dozens of labourers.

Afghan President Hamid Karzai said 31 US special forces and seven Afghan soldiers were killed in a helicopter crash in eastern Wardak province.

Six Nato service members were killed today in an insurgent attack in southern Afghanistan, the international alliance said in a statement.

Up to 30 insurgents have been killed in fighting ahead of this week’s parliamentary elections in Afghanistan, Nato and Afghan officials said today.