Beijing ? The crew of a Chinese airliner bound for Beijing thwarted an attempt to crash the plane last week, a Chinese government official said Sunday.

The plane had taken off from the region of Xinjiang in northwestern China, where police in January raided an office of an ethnic minority separatist group. Police said at the time that they had killed two suspects and arrested 15.

The Communist Party chief of the region, Wang Lequan, disclosed Sunday that the raid had uncovered materials indicating the planning of an attack on the Beijing Olympics, which begin Aug. 8.

“Their goal was very clear,” Wang told reporters on the sidelines of the National People’s Congress here.

The China Southern Airlines flight, which departed the regional capital of Urumqi at 10:35 a.m. Friday, was forced to land about two hours after takeoff because “some people were attempting to create an air disaster,” Nur Bekri, chairman of the Xinjiang regional government, told reporters at the same gathering at which Wang spoke Sunday afternoon.

Bekri, who gave few details of the incident, said authorities were investigating “who the attackers are, where they are from and what’s their background.”

“But we can be sure that this was a case intending to create an air crash,” he said.

Chinese officials said last year that terrorism was their top security concern for the Summer Olympics.