KABUL, Afghanistan -- Nine NATO service members were killed yesterday in Afghanistan, including seven U.S. troops who died when a powerful bomb exploded in a field where they were patrolling on foot, officials said.
Two Afghan policemen also died and two others were wounded in the explosion in the mountainous Shorabak district of Kandahar province, 12 miles from the Pakistan border, said Gen. Abdul Raziq, chief of the Afghan border police in the province.
"Two months ago, we cleared this area of terrorists, but still they are active there," Raziq said.
The Taliban claimed responsibility. "A bomb was planted for them in a field," Taliban spokesman Qari Yousef Ahmadi told The Associated Press in a telephone call.
The international military coalition reported that another NATO service member was killed yesterday when a helicopter crashed in the east.
U.S. officials said seven American soldiers were killed in the bombing.
It was the deadliest day for coalition forces in Afghanistan since April 27, when a veteran Afghan military pilot opened fire at Kabul airport and killed eight U.S. troops and an American civilian contractor.
Yesterday's blast was the worst single attack against NATO forces by one of the Taliban's crude, homemade bombs since October 2009. Seven soldiers from a unit based in Fort Lewis, Wash., died Oct. 27, 2009, when their vehicle hit a roadside bomb, also in Kandahar province.
"It was a big, powerful blast," said Gen. Tefeer Khan Ghogyaria, who oversees Afghan border police in three provinces in the south. "A container of explosives was placed in the ground and it exploded when the NATO forces were passing. They were on a foot patrol."
Roadside bombs killed 268 American troops in Afghanistan last year, a 60 percent increase over the previous year, even as the Pentagon employed new measures to counter the Taliban's makeshift weapon of choice. Defense officials attributed the rise in casualties to the surge in U.S. forces in Afghanistan last year.