A transport helicopter crash that killed five American crew members supporting operations against insurgents Sunday appeared to be an accident, a U.S. military statement said.
The twin-rotor CH-47 Chinook helicopter went down in a remote, mountainous area southwest of the village of Dai Chopan in southeastern Afghanistan.
U.S. and Afghan forces have fought frequent battles with the Taliban and their militant allies in the area for several years, and the downed helicopter had just dropped off American troops to search for rebels.
"There is no indication of enemy involvement in the crash," the U.S. military statement said.
All five crew members onboard the Chinook were killed. The military did not identify them but said the crash was under investigation.
Sunday morning, the copter delivered troops in the Dai Chopan district of Zabol province, about 190 miles southwest of Kabul, said Gulab Shah Alikheil, spokesman for the provincial governor. The personnel were on a mission to hunt for suspected Taliban fighters hiding in the area, he added.
"This was not a very big operation," Alikheil said Sunday by telephone from the provincial capital, Qalat. "I think they have surrounded a house where the suspected Taliban militants were hiding, and I also think they have arrested them."
The U.S. and Afghan military reported that the Chinook crashed on its way back to base and "the possibility of a technical problem is higher than an attack," Alikheil added.
It was the fourth major crash of a foreign military helicopter in Afghanistan this year.
In April, 18 Americans died in a Chinook crash just outside the southeastern provincial capital of Ghazni. Investigators blamed a dust storm.
In late June, insurgents shot down an MH-47 transport chopper, a special operations version of the Chinook, with a rocketpropelled grenade in the eastern province of Kunar.
Sixteen U.S. Army and Navy Special Forces troops, who were trying to rescue a four-man Navy SEAL reconnaissance team that had been ambushed by guerrillas, died in that crash. One of the SEALs survived by taking shelter in a shepherd's home.
In August, 17 Spanish soldiers died when their Cougar AS532 helicopter crashed in western Afghanistan during a training mission before the national elections of Sept. 18. The crash also was ruled an accident.
This year has been the deadliest for U.S. forces since the Taliban regime was overthrown in 2001. At least 51 Americans have died in combat; an additional 30 have died in nonhostile action, including accidents such as drownings, explosions and crashes.
The conflict has killed about 1,200 Afghans, many of them insurgents, this year.
There has been a lull in large-scale attacks since the balloting last week, when millions of Afghans defied Taliban threats and voted for members of the lower house of parliament and 34 provincial councils.
Insurgents killed at least seven candidates, four election workers and numerous people carrying voter registration cards in the weeks before the election, but voting day was mainly peaceful.
"After the election, we have seen some very small attacks, like a rocket attack and this small operation in Dai Chopan," Alikheil said.
"Everything is normal until now, but I think Al Qaeda and the Taliban are very weak at the moment."
Around 6.8 million, or 54% of about 12.5 million registered voters, turned out to cast ballots, the joint United Nations and Afghan body overseeing the election said Sunday.
An estimated 43% of eligible women voters and 57% of registered men cast ballots, said Peter Erben, chief electoral officer.
The women's turnout was surprisingly high in some provinces where the Taliban is strong and traditional ethnic Pushtun values limit women's activities outside the home.
The final ballot count is expected early next month.