An Air China flight was forced to make an emergency landing in southwest China's Chongqing Municipality on Wednesday due to a bomb scare, Xinhua news agency reports.

Flight CA1336 flying from Nanning City in south China's Guangxi Zhuang Autonomous Region to Beijing was forced to land in Chongqing airport at 1:59 p.m. after taking off about one-and-a-half hour earlier.

Sources with Air China Chongqing branch said a passenger had claimed that an explosive device was on board the plane.

Witnesses said emergency services were at the airport.

Three passengers were held by police for questioning as of 5 p.m. Wednesday.

The rest of the passengers continued their flight to Beijing after a security check.

Investigation continues.