KABUL, Afghanistan -- A NATO helicopter killed more than 20 insurgents after it was fired on during an operation in Afghanistan's restive Kandahar province, the coalition said Friday.

The group of fighters shot at the helicopter with small arms and machine guns, a NATO statement said. A ground team later found 20 bombs, firearms and several vehicles.

A NATO service member was also killed in a separate incident.

The fighting occurred Thursday during an operation to flush out insurgents in the Spin Boldak district, said provincial border police chief Abdul Raziq. He said 300 police were deployed alongside NATO troops and that three Afghan police officers died when their car hit a mine.

NATO said initial reports showed there were no civilian casualties during Thursday's fighting. The coalition tightened its rules of engagement last year after complaints its air raids frequently killed civilians instead of insurgents. Since then, reports of civilian deaths caused by NATO have dropped by a third.

In a separate incident, a NATO service member died after an insurgent attack in southern Afghanistan on Friday. The NATO statement did not provide nationality or further details.
NATO and Afghan forces began pushing into the insurgency's heartland in southern Afghanistan in July but attacks in other areas of the country have shot up.

In western Herat province, insurgents surrounded a checkpoint manned by local police in Chishti Sharif district on Friday afternoon and opened fire, killing 10 officers and wounding 12, said district police commander Gulbuddin. He goes by a single name.

Both the west and the north, traditionally considered more secure, have seen an upsurge in attacks, kidnappings and assassinations since the offensive against the Taliban began in the south.