TAIPEI, Taiwan - Taiwan was angry yesterday about a World Health Organization decision to keep a SARS travel advisory for the island but lift it for Canada, where - despite the WHO vote of confidence - a recent U.S. visitor caught the virus before returning home.

Meanwhile, a top WHO disease expert sought answers from Beijing about a sharp drop in reported SARS cases there that has not matched more gradual decreases elsewhere. He declined to say whether WHO was considering lifting a travel advisory for the Chinese capital.

WHO considers the export of SARS cases a key factor in deciding to impose travel advisories, which governments are eager to avoid because of the cloud it casts over tourism.

But WHO said Tuesday it decided against reinstating a travel warning to Canada's largest city, Toronto, despite the sickened U.S. traveler and a new suspected hospital outbreak in the Toronto area. WHO spokesman Iain Simpson said the agency has not confirmed that Toronto exported the case.

Meanwhile, Taiwanese officials said yesterday that WHO rejected the island's request to have its advisory canceled because the agency feared Taiwan might be exporting SARS cases.

Simpson told the Associated Press that Taiwan has met only one of three key requirements for canceling the travel warning - showing that its most recent three-day average of new cases is five or fewer.

But Taiwan has to meet two other requirements: having fewer than 60 active cases in hospitals, and being able to show that the virus is not being exported, Simpson said.

Steven Kuo, spokesman for Taiwan's SARS Control Committee, told the AP that the latest count yesterday showed the island's hospitals had only 27 active patients, or people who got sick within the past two weeks.

Severe acute respiratory syndrome has infected more than 8,300 worldwide and killed at least 790, most of them in Asia.

WHO is especially concerned about a Taiwanese traveler who developed SARS symptoms in Sao Paulo, Brazil, on June 4. The other sick travelers - who left Taiwan between March 4 and May 22 - went to the United States, South Korea, the Philippines, Germany and Thailand, he said.

Taiwan, the world's No. 3 SARS hotspot, has reported 81 deaths and 687 cases. But in recent days, the number of new cases has plunged, and a death has not been reported in 14 days.

The Toronto infection involved a U.S. man who visited the city last month and came down with the illness after returning to his home near Raleigh, N.C. American health officials confirmed Monday that he developed SARS.

The man visited a Toronto hospital patient who was sharing a room with people who later came down with SARS, officials said. His diagnosis raised the possibility of SARS spreading from people carrying the virus but not showing symptoms.

Toronto has been linked to 11 - or 16 percent - of the U.S. probable cases, said Llelwyn Grant, spokesman for the U.S. Centers for Disease Control and Prevention.

The Canadian city has had the highest concentration of SARS cases outside of Asia, with 33 deaths and 216 cases reported, making it the world's No. 4 trouble spot. Officials reported 64 probable cases Tuesday, down two from the previous day.