KABUL, Afghanistan - Seven American troops, two Australians and a French Legionnaire were killed in the bloodiest day this year for international forces in Afghanistan. A US contractor training Afghan police also died in a brazen suicide attack.

The bloodshed on Monday came as insurgents step up bombings and other attacks ahead of a major NATO operation in the Taliban stronghold of Kandahar that Washington hopes will turn the tide of the nearly nine-year-old war.

Half the NATO deaths - five Americans - occurred in a single blast in eastern Afghanistan, US spokesman Colonel Wayne Shanks said. Two other US troops were killed in separate attacks in the south - one in a bombing and the other by small arms fire.