A domestic flight from Urumqi to Hubei turned into a security drama yesterday after a passenger set fire to toilet paper in the washroom, forcing the aircraft to return to the Xinjiang capital. Xinhua said a man and a woman were arrested after the flight landed at the Diwobao International Airport in Urumqi. It did not give the identities or ethnicity of the two people. Security has been tight in Xinjiang, which has been on knife edge since ethnic riots in July, and yesterday's scare was similar to a 2008 incident in which a Uygur woman tried to bring down a flight to Beijing by starting a fire in the toilet. Xinhua said crew of China Southern Airlines flight CZ6939 - bound for Hubei's capital Wuhan - discovered the passenger's action after take-off. It did not explain why two passengers were arrested. Customer service officers for Southern Airlines said the flight had been scheduled to fly to Wuhan via Xian , the capital city of Shaanxi . It was to depart at 3pm, but was delayed about 30 minutes due to 'mechanical failure and passenger-related causes'. The officers claimed that they did not know details of the incident, but said all passengers were safe. The flight eventually left for its scheduled destinations after a 30-minute delay. A duty officer at the Diwobao International Airport's Public Security Bureau confirmed two people were arrested, but refused to give details. 'As I know, the case is still under investigation,' she said. Xinjiang has been tense since July, when clashes in Urumqi between ethnic minority Uygurs and majority Han Chinese residents left at least 197 people dead and injured up to 2,000. In the security crackdown that followed, Xinjiang was shut off from the outside world with bans on international calls, access to the internet and text messaging. Those services have been gradually resuming since last month. But even before the riots last year, there were other incidents on flights from Urumqi. In March 2008, Xinjiang's governor Nur Bekri said a Southern Airlines cabin crew had foiled a plan by an ethnic Uygur woman to bring down a flight from Urumqi to Beijing. Local media said that the woman tried to light flammable liquid, which she had smuggled on board, in the plane's toilet, but aroused the suspicion of crew and other passengers. On August 9 last year, China's civil aviation authority refused to allow an international flight from the Afghan capital Kabul to land at Diwobao International Airport. Officials said they had received information that the aircraft had been hijacked or that terrorists had placed a bomb on board. The flight, the maiden journey to China by private airline Kam Air, returned to Kabul without incident. Official media said this month that funding for public security in the autonomous region would nearly double this year. A budget proposal placed before Xinjiang's legislature called for 2.89 billion yuan (HK$3.3 billion) to be spent on public security, up from 1.54 billion yuan last year. Authorities also issued orders to step up identity checks and monitor religious activities in Xinjiang. The central government is due to hold the first Xinjiang Work Symposium - a high-level meeting expected to be attended by the Politburo Standing Committee - to set guidelines for the region's development.