An explosion hit Beijing Capital International Airport's Terminal 3 on Saturday, with a man in a wheelchair apparently detonating a device.
Photos posted on China's version of Twitter, called Weibo, showed the man waving a white package in the air before the blast, which was heard at 6:24 p.m. local time.
Nobody was killed or injured in the attack.
The bomber was reportedly beaten by Chinese police in 2005, causing his lower body to be paralyzed. He was unable to work afterwards.
The man, identified as Ji Zhongxing, was born in 1979 in Shandong Province. He was handing out leaflets at the airport just before the explosion, witnesses say.
He was apparently unhappy with how the authorities treated his complaints against the police.
It is common for disgruntled Chinese workers to seek justice using petitions rather than going to courts, which are seen as tools of the Communist leadership.
Sky News Asia correspondent Mark Stone tweeted a photo of what is reportedly the moment the device was detonated.
Later images showed the wheelchair on its side with officials treating the man on the floor. He was reportedly sent to a hospital.
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Flights were not affected by the explosion and order was quickly restored to the airport.
Daily Telegraph correspondent Malcolm Moore posted on Twitter a photo of debris being cleaned up after the small blast.
He also said the bomb used was self-made from fireworks.
The airport's news office told the Associated Press that it was not aware of the explosion and airport police declined to answer questions.