Asia's first case of swine flu was today confirmed in Hong Kong, sparking an emergency alert over the virus in the densely-populated former British colony, dpa reported. The 25-year-old male patient is a visitor from Mexico (the worst-hit country in the swine flu outbreak) who flew to Hong Kong from Shanghai Thursday and was staying at a hotel in the city's Wan Chai district. The patient was taken to hospital and later transferred to an isolation ward at Princess Margaret Hospital where he was in a stable condition Friday evening, Chief Executive Tsang said at a press briefing. The hotel where the patient was staying, the Metropark, was Friday quarantined with all guests barred from leaving. Guests told government-run radio station RTHK the hotel was "completely cordoned off." Government officials said later all guests inside the hotel would be quarantined for seven days as part of the city's rigorous anti-flu safeguards. Health workers in protective clothing and face masks were seen walking in and out of a cordon set up around the hotel with police guarding all entrances. Efforts were meanwhile being made to trace passengers who travelled with the man on a China Eastern flight to Hong Kong from Shanghai on Thursday to test them for symptoms. Tsang announced the case after a meeting of top government officials was convened in response to news of the patient, who was confirmed as having swine flu at 8 pm (1200 GMT) Friday. The Hong Kong leader appealed to the public not to panic and said everything would be done to prevent the virus from spreading in the high-rise city of 7 million. "I would urge Hong Kong citizens not to panic," Tsang said. "School classes, public exhibitions and economic activities can all proceed as usual. He said Hong Kong's rapid response was aimed at stopping the virus spreading. "I would rather take a stricter approach than miss the opportunity to contain the virus before it spreads," Tsang said. Hong Kong has raised its swine flu alert level from "serious" to "emergency" in response to the confirmation of the case. Full details of the heightened measures were due to be announced later. Health Secretary York Chow appealed to the public to help find fellow airplane passengers and the taxi driver who took the Mexican to his hotel to contact officials so they could "look after them and give the relevant medicine." Two holidays camps in rural areas of Hong Kong had been prepared to act as isolation units for people suspected to have contracted swine flu, Chow said. News of the case came after Tsang warned earlier this week that Hong Kong was at a greater risk of a swine flu outbreak because it is one of the world's most densely populated cities. Before Hong Kong's announcement of its case, the World Health Organization said Friday that 331 human cases of swine flu have been reported in 11 countries. Ten cases have been fatal - nine in Mexico and one in the United States. Ironically, the first case of severe acute respiratory syndrome, or SARS, in Hong Kong in 2003 was a man from China who stayed at another hotel in the city. A total of 299 people died and about 1,800 were infected with the SARS virus in the city of 7 million, and the virus spread from Hong Kong around the world. Many of those cases were subsequently traced back to the hotel visitor from China.