NATO rockets kill 12 Afghan civilians

The incident occurred in Nad Ali, an insurgent-infested area where British troops are operating. A Ministry of Defence spokeswoman said the rockets, which were fired by a sophisticated missile system, were a "US responsibility".

News of the deaths overshadowed cautiously optimistic reports from US commanders in nearby Marjah, a major hub of insurgents and drug smugglers, where marines and Afghan soldiers pushed deep into a labyrinth of mud-walled compounds surrounded by landmines and booby traps.

The soldiers went carefully, preceded by explosives teams and sniffer dogs. Taliban snipers holed up in farmhouses offered sporadic, and sometimes sustained, resistance. One group came under fire moments after they hoisted an Afghan flag over a newly captured compound.

Elsewhere, gunfire forced the operation's American commander, Brigadier General Larry Nicholson, to take cover behind an earthen bank. "The fire we just took reflects how I think this will go, small pockets of sporadic fighting by small groups of very mobile individuals," he told an embedded AP reporter.

Operation Moshtarak (meaning "together") involves 15,000 troops, mostly US, British and Afghan. The first US marines arrived in Marjah by helicopter before dawn on Saturday morning, while British forces are sweeping through Nad Ali.