Insurgents in eastern Afghanistan shot down a NATO Chinook helicopter during an overnight operation killing 37 people on board, a military official said on Saturday.

Along with the majority of NATO troops who were killed, Afghan soldiers also lost their lives, an unnamed official said.

The helicopter was hit by a rocket-propelled grenade in the Tangi valley of the Wardak Province just west of Kabul. The Taliban claimed credit for the attack.

Though the reports of the crash are confirmed, no further information, including the cause of the crash, has been provided by NATO spokesman,

There is uncertainty lingering over the accounts on when the helicopter went down.

Taliban spokesman Zabiullah Mujaheed said that the insurgents shot down the helicopter around 11 p.m on Friday as it was launching an operation on a house where the militants were gathering in the Tangi Joyee region of Saydabad District in the eastern part of the province. Eight militants were killed in the fight that continued after the helicopter fell, he said according to the report.

"The fresh reports from the site tells us that there are still Americans doing search operations for the bodies and pieces of the helicopter are on the ground," Mujaheed added.

According to Gen. Abdul Qayoom Baqizoy, police chief of Wardak, the operation that lasted around two hours, began around 1 a.m on Saturday as NATO and Afghan forces attacked a Taliban compound in Jaw-e-mekh Zareen village in the Tangi valley, NYTimes reported.

The Tangi valley is situated along Wardak border.