Four NATO soldiers killed in Afghan bomb attack

KABUL (Reuters) - Four members of the NATO-led International Security Assistance Force were killed on Wednesday in an improvised explosive device (IED) attack in southern Afghanistan, the alliance said in a statement.

The 150,000-strong force is suffering mounting casualties as an operation continues to take on the Taliban in their southern heartland, and June saw over 100 troops killed -- the bloodiest month of the nine-year-old war.

Another ISAF member died on Wednesday in a separate insurgent attack, also in the south, NATO said.

The alliance rarely gives more details on casualties, leaving home nations to first contact next of kin.

Used mostly as roadside bombs, IEDs are now a common weapon of the resurgent Taliban in their campaign against foreign and Afghan forces.

Wednesday's deaths bring to 12 the number of foreign troops killed in the past 24 hours.

In the most shocking incident, three members of the British Gurkha regiment were killed when an Afghan National Army soldier they were serving alongside turned on them with a machine-gun and rocket-propelled grenade (RPG) before escaping.

NATO and Afghan troops increasingly fight side-by-side against the Taliban as the West tries to pass on more responsibility for security ahead of a gradual withdrawal starting next year.

Officials and politicians have stressed that the policy will continue, but complete trust in your fellow troops is the cornerstone of any fighting force, and the incident would have shaken.

The rapid creation of a national army and police force since the Taliban's ousting and following decades of war has seen tens of thousands of Afghans join the security services, and there are fears insurgents may also have signed up.

The complexity of the Afghan war was further highlighted by the deaths of five civilian Afghan translators working for ISAF forces in Kandahar.

Three ISAF troops also died in the attack, with insurgents staging a commando-style raid on a police post after a suicide bomber rammed a car laden with explosives into the main gate.

(Editing by Ron Popeski)