Hong Kong health officials on Sunday reported 60 more people had fallen ill with a deadly flu-like disease, more than half of them in one apartment complex, pushing the number of infections worldwide past 1,600.

Hong Kong and Singapore each reported one new death from severe acute respiratory syndrome, or SARS, bringing the global toll to at least 57.

Thailand and Singapore stepped up monitoring at airports, while the U.S. Centers for Disease Control and Prevention suggested postponing nonessential travel to mainland China, Hong Kong, Singapore or Hanoi.

The U.S. experts warned that no treatments tested against SARS has been effective, and Singapore's health minister said that the disease is more contagious that previously thought and that some people could transmit it to as many as 30 or 40 others.

"We run the risk of a huge new cluster of infected people, which could start a chain reaction," Health Minister Lim Hng Kiang told a news conference.

The World Health Organization has expressed concern over the increasing spread of the disease in Hong Kong, where new SARS cases have picked up pace in the past few days. Hong Kong is the second-hardest hit place after mainland China, which has reported some 800 cases and 34 deaths.

Hong Kong has now reported 530 cases of SARS, although officials also noted that 60 patients here have recovered and been discharged. A 74-year-old woman, with a history of health problems, became Hong Kong's 13th fatality early Sunday.

Thirty-six of the new cases of SARS came from Hong Kong's Amoy Gardens apartment complex, where a victim recently spread the disease and it took hold, according to a Health Department statement. Some frightened residents have moved out and medical teams have gone through the apartments to check for SARS — while some minibus drivers won't even stop there anymore.

Between 110 and 120 SARS cases have come from Amoy Gardens, which is located in Kowloon Bay, a government spokeswoman said Sunday night, using customary anonymity.

The Geneva-based WHO says the disease is spreading via international travelers, and nations across Asia are fighting to contain the illness.

Taiwan's premier urged citizens on Sunday to postpone visits to China for the traditional Ching Ming tomb-sweeping festival, as the island announced its 13th SARS case. Thousands of Taiwanese had been expected to fly to China this week to worship ancestors and sweep their tombs in the festival Saturday.

Thailand stepped up monitoring at airports and border checkpoints Sunday. About a dozen visitors were quarantined, but most were quickly released when it became apparent they did not have SARS.

The vigilance followed the death in a Thai hospital of an Italian WHO expert on communicable diseases who identified the SARS outbreak in Hanoi. He had been receiving treatment in Thailand after becoming infected in Vietnam.

Singapore said nurses would screen all travelers arriving from infected areas. The city state has reported 91 cases and 12 of those people were in critical condition. It reported a third death Sunday.

SARS spread to other countries from Hong Kong after a sick mainland Chinese medical professor passed the illness to seven other people in a Kowloon hotel last month and they, in turn, carried the disease to Singapore, Vietnam and Canada.

Hong Kong health officials said Sunday that a man who came down with the illness had been aboard Dragonair flight KA901 from Beijing-Hong Kong on Wednesday and they were trying to trace the other 222 passengers and 15 crew to see if they were infected.

The spread of the disease has sent jitters through Hong Kong. Thousands of people have put on surgical masks, taxi drivers were cleaning out their cars, concerts and protests were canceled. The horse-racing track in suburban Shatin saw its lowest attendance ever on Saturday as many of the territory's fervent gamblers stayed home.

On Sunday, religious groups prayed to ease fears about the disease in Hong Kong.

About 50 people from Christian churches gathered in a downtown park and displayed a banner that said: "Don't be afraid, just believe." The Taoist Wong Tai Sin Temple held a six-hour prayer session for world peace and an end to the SARS outbreak.