Chinese passengers walk through a scanning machine at the entrance of Shanghai Hongqiao International Airport in Shanghai, China, 21 July 2013. Chinas airports have enhanced security measures after a disabled man set off a bomb on Saturday (20 July 2013) at Beijing Capital International Airport. Explosives checks are being carried out at the entrances of the arrival and departure halls at the airport, with security personnel swiping palm-sized testing paper on passengers luggage. SWAT officers have been deployed in the halls, Beijing police announced on Sunday, and police dogs have also been deployed. The anti-explosive measures came after an incident on Saturday evening when Ji Zhongxing, 34, set off a homemade bomb at the Beijing airport, injuring himself and a security guard. The explosion occurred outside Gate B of the Terminal 3 arrival hall, where people don't need security checks. Beijing police said on Sunday that Ji had been taken into custody and they were investigating how he got the explosives, what his motives were and whether there were any other suspects. Airports in many other cities, including Shanghai and Shenzhen, have also upgraded security measures. Shanghais Pudong and Hongqiao international airports have been checking for explosives at exits and entrances since Sunday, according to the Shanghai Airport Authority, which operates the airports.