Marine Gen. Peter Pace, the chairman of the U.S. Joint Chiefs of Staff, is visiting Afghanistan ahead of the NATO's assumption of command from the coalition of security operations in southern provinces where the Taliban have stepped up attacks this year.

The Taliban "may be a day-to-day tactical problem for us, but we are a long-term strategic problem for them," Pace was quoted as saying Thursday by the Department of Defense web-site. "They can pick and choose some battles, but they cannot take over this country again."

Afghanistan is in the midst of its deadliest violence since the U.S.-led invasion in late 2001 that toppled the Taliban regime for hosting Sept. 11 attacks mastermind Osama bin Laden.

Two coalition soldiers were wounded in the troublesome Sangin district of southern Helmand province on Thursday during a clash with Taliban rebels, said Maj. Scott Lundy, a coalition spokesman. He did not disclose the soldiers' nationality.

He said their conditions were not life-threatening.

Also Thursday, the coalition used artillery to kill three suspected Taliban rebels holed up in a house following a failed ambush on a coalition convoy in the Zhari district of southern Kandahar province, a coalition statement said.

More than 10,000 U.S., Canadian, British and Afghan troops are in the midst of a large-scale anti-Taliban offensive across the south, preparing the ground for the mission of the NATO-led security force to stabilize the area.

The coalition says more than 600 Taliban have been killed in the offensive since June 10.

Meanwhile, three of those killed in a helicopter crash in eastern Afghanistan earlier this week were identified as the wife and two daughters of an American civilian contractor.

Up to 16 people were killed when the Russian-made Mi-8 helicopter - owned by the Afghan government and operated by a private company - crashed in mountains about 40 kilometers (25 miles) northeast of Khost city on Wednesday. Officials have yet to establish the cause of the crash.

Afghan and U.S. troops recovered 12 bodies Thursday and were searching for four others in the forbidding mountainous terrain. Among the dead were two Dutch military officers - the first Dutch military fatalities in Afghanistan.

The three Americans were identified as Darlene Moulder, 55, and daughters Bryn, 21, and Caroline, 17, of Atlanta. They were traveling to Khost to meet with Stuart Moulder, a civilian working with the U.S.-based firm Fluor, and then go on a family vacation, his sister, Carol Dallas, told WAGA-TV of Atlanta.

Fluor does construction work in Khost. Officials said there were no survivors from the crash.

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