The US Air Force has confirmed the crash of a Boeing KC-135 flying from its base in Manas, Kyrgyzstan.
Kyrgyzstan's emergencies ministry has also confirmed the crash of a large transport aircraft west of the capital Bishkek, and identifies the jet as a Boeing 707 tanker, probably signifying the KC-135 version of the civil airframe.
It states that the aircraft was associated with the Transit Centre at Bishkek's Manas international airport.
The aircraft came down at 14:55 local time in the Panfilov district, between the villages of Cholok-Arik and Chorgolu, some 90km west of Bishkek, near the border with Kazakhstan.
There is no immediate information on the number of occupants or whether there are casualties.
Manas' Transit Centre became active in late 2001 during the deployment of coalition forces involved in operations in Afghanistan. The centre performs aerial refuelling, airlift and troop movement services.
Images of the crash scene and part of the aircraft's tail indicate that the tanker involved was registered as 63-8877. Flightglobal's MiliCAS database records this KC-135R as having entered use in 1964. Tail markings show that the aircraft was home based at McConnell AFB in Kansas.
The KC-135 is routinely operated with a three-person crew, comprising two pilots and one boom operator.