Three Nato soldiers have been killed in a bomb explosion in western Afghanistan. The Nato-led International Security Assistance Force (Isaf) said, the three troops were killed when an improvised explosive device went off. The latest violence comes as the Taliban denied it has had secret contacts with the Afghan government. Isaf has not given details of the nationalities of the dead soldiers. Six soldiers were killed in attacks in southern and eastern Afghanistan yesterday, bringing the total tally of Nato soldiers killed in Afghanistan this month to 30.