Five people were arrested in China's Hebei province on suspicion of being involved in an online firearms sales network, a media report said on Sunday.
According to provincial authorities, the suspects were illegally manufacturing guns and components such as bolts, triggers and barrels since July 2014, the Global Times reported.
Police said that the suspects' distribution network may have spread to as many as 30 provincial regions, including Beijing and Shanghai. Evidence showed that some items were sent from Taiwan and the US.
Nine air rifles and more than 3,000 bullets were confiscated from the suspects.
China's criminal law states that illegally manufacturing and selling guns could lead to up to 10 years in jail.