Three Nato troops and five Afghan soldiers were killed in Taliban attacks on their patrol in southern Afghanistan, the alliance said Friday, raising the number of international forces slain in the first week of August to 18.

Nato said the troops' vehicle was hit by a roadside bomb before insurgents opened fire. The Nato forces fired back, but the three were killed.

Attacks killed at least 75 troops from the US and other international military forces in July, the highest death toll for a single month since 2001, according to military reports.

Afghan officials said roadside bombs had killed five policemen and an Afghan guard in the south, the centre of the Taliban-led insurgency, where thousands of new US and British forces are trying to secure roads and population cen-

tres ahead of the Aug. 20 presidential election.

On Thursday a roadside bomb killed 21 Afghans heading to a wedding, the latest in a wave of violent attacks ahead of key election's* as the Nato chief Thursday assessed efforts to quell the insurgency.

A US soldier, five Afghan policemen and two truck drivers were also killed in a series of extremist strikes, which have raised fears that violence will mar voting in Afghanistan and damage the credibility of the August 20 polls.

A trailer packed with guests invited to a wedding and towed by a farm tractor -- a common mode of transport in rural Afghanistan --was hit Wednesday in the southern province of Helmand, government officials said.

The insurgents have pledged to disrupt the vote and have dramatically increased their use of roadside bombs against foreign and Afghan forces.