At least 27 servicemen were killed when a Tajik National Guard helicopter crashed in the mountainous Rasht valley in eastern Tajikistan, a police source said on Wednesday, RIA Novosti reported.
About 20 member of elite units of the Alpha National Security State Committee and seven members of the National Guard, including a colonel and two lieutenant-colonels were among those killed, the source said.
Tajik security forces launched an operation against insurgents in the Rasht region two weeks ago following the deaths of 26 servicemen in an attack on a military convoy on September 19. Fourteen soldiers were injured in the ambush.
Since the operation began, 15 militants have been killed.
The Mi-8 helicopter crashed due to technical reasons, the National Guard said.
A probe into causes of the crash is ongoing.