'Two of [the groups], one from Hong Thai and another from Wing On, are now in Urumqi. They are all safe,' Mr Tung said, adding that the National Tourism Administration on the mainland had informed him that calm had been restored.

He said that Urumqi, capital of Xinjiang, was a travel hot spot for Hongkongers bound for Xinjiang. 'Travel agencies would closely monitor the situation and there is no plan to cancel any tour to Xinjiang now,' he said.

Daniel Chan Kin-pang, Hong Thai's deputy general manager, said a tour group of 10 and their guide had arrived in Urumqi yesterday afternoon. 'They left Turpan [on Monday] morning and reached Urumqi,' Mr Chan said. Turpan city is about 150 kilometres southeast of Urumqi. 'They were to have visited a giant marketplace operated by Uygurs, but the market has been shut for three days, so we took them to the peak area instead.'

He said the group, which left Hong Kong last Monday, would head to Xian today as scheduled. 'They are very safe now in Urumqi. But we advised them to stay in the hotel and not to go out at night.'

Wing On's tour group, of 20, also arrived in Urumqi yesterday, a spokeswoman said. 'Now they will stay in Urumqi for only one day instead of two due to the situation there,' she said. 'They are safe and staying at a hotel that is far away from the urban centre. They will head to Turpan on Tuesday morning.'

Hong Kong's Security Bureau and the Hong Kong government's office in Beijing say they are closely monitoring the situation. 'We understand that Hong Kong tour groups there have adjusted their travel plans to avoid the affected areas,' a bureau spokesman said.

'The Security Bureau also advises Hong Kong residents there to pay attention to their personal safety. Residents who need assistance while outside Hong Kong may call the 24-hour hotline of the Assistance to Hong Kong Residents Unit of the Immigration Department on (852) 1868.'