The Il-76 plane, a four-engined heavy transport aircraft, dropped from the sky two minutes after taking off from Urumqi airport at 10:50 am (0250 GMT), sparking ear-shattering explosions and a pall of thick black smoke, Xinhua news agency said.

Cargo and debris from the crash was scattered over a two kilometer (more than a mile) wide area, which was sealed off as crowds of onlookers gathered, said witnesses, who believed the pilot was attempting an emergency landing.

"The plane touched down in a cotton field but kept sliding, with its fuselage resting on one side and its left wing poking into the earth," said Ma Yuelan, a taxi driver who saw the crash.