Media playback is unsupported on your device Media caption The wreckage is scattered across a wide area of mountainous terrain

A search is under way for the three crew of a US military refuelling plane that crashed in northern Kyrgyzstan.

The KC-135 Stratotanker disappeared off the radar near Chaldovar village, some 160km (100 miles) west of the base near Bishkek from where it took off.

Witnesses said they saw the plane, believed to have been laden with fuel at the time, explode in mid-air.

The wreckage is scattered across a wide area. US officials said: "The status of the crew is unknown".

Kyrgyz media quoted some witnesses as saying they saw at least one pilot escape the burning plane - one report said by ejector seat - but these accounts have not been substantiated.

Contentious airbase

Kyrgyz officials said the plane had taken off from the US transit centre at Manas international airport, near Bishkek, with some 70 tonnes of fuel on board.

It crashed at around 15:00 local time (09:00 GMT).

"I was working with my father in the field, and I heard an explosion. When I looked up at the sky I saw the fire. When it was falling, the plane split into three pieces," resident Sherikbek Turusbekov was quoted by the Associated Press as saying.

In a statement, the US transit centre confirmed the crash and said "emergency response crews are on the scene". "The cause of the crash is under investigation," the statement added.

An unnamed defence official in Washington told the Associated Press that the plane was on a refuelling mission to Afghanistan at the time.

The scene of the crash was being guarded overnight, and officials said a search for the missing crew members would resume in the morning.

The base at Manas has been used by the US military since 2001 as a hub for its operations in Afghanistan.

The United States is leasing the facility for $60m a year and wants to extend the lease beyond its end date of June 2014. Kyrgyzstan is reluctant to extend the lease, saying the presence of the base is a threat to its security.

Seven crew members died when a US civilian Boeing 747 cargo plane crashed at Bagram airbase in Afghanistan on Monday.