Xinhua News Agency did not identify the airline or the type of plane, but said the Urumqi airport had been told not to allow the plane to land. It said police and emergency vehicles had been rushed to the airport.
Urumqi, the capital of Xinjiang, was the scene of the worst ethnic violence in China in decades when deadly rioting killed 197 people and injured more than 1,700, according to official count.
A Xinjiang regional government duty officer, who refused to give his name, said he had not received any information about the incident, while calls to the region's public security bureau rang unanswered.
Calls to the Urumqi airport's information counter also rang unanswered.
The government has said that Urumqi has slowly been returning to normal since the rioting erupted on July 5 after police stopped a protest by ethnic Uighur residents. The Uighurs went on a rampage, smashing windows, burning cars and beating Han Chinese, the nation's dominant ethnic group. Two days later, the Han took to the streets and attacked Uighurs.
The government said the violence was the work of terrorists, separatists and foreign forces as part of a plot to carve up China.
In early August, an Internet message purportedly from the leader of an Islamic group fighting Chinese rule in a western province urged Muslims worldwide to attack Chinese interests in retaliation for what it called the oppression of minority Uighurs. State media reported in March 2008 that a 19-year-old Uighur woman was detained after trying to set a fire in an airplane bathroom in an attempt to hijack and crash the flight. No one was injured and the plane landed safely.