Hong Kong ? Despite major quarantines and school closings meant to contain a deadly flu-like disease, more cases cropped up Friday as health officials in Hong Kong and Singapore warned of the worst public health crisis in years.

“We are facing an unprecedented situation,” said Singapore Health Minister Lim Hng Kiang. “Singaporeans must understand that this is for the long haul — this is not going to turn around anytime soon.”

Singapore doubled the number of people under quarantine, adding those who came into contact with hospital workers treating patients of the disease. There now are 1,500 people confined to their homes for about two weeks. The quarantine in Hong Kong totaled 1,000.

Hong Kong’s health secretary predicted still more people would become infected with severe acute respiratory syndrome, SARS.

As 58 more people in Hong Kong became sick with symptoms of the disease Friday, Dr. Yeoh Eng-kiong said the SARS epidemic was a tougher challenge than the 1997 chicken flu outbreak that killed six people.

“The bird flu was simpler,” Yeoh said. “All you had to do was kill the chickens. Now you’re dealing with humans.”

SARS is blamed for 11 deaths here — the hardest-hit area outside of mainland China, where the disease apparently started months ago. More than 400 Hong Kong residents are sick with the disease. In Singapore, two people have died and 86 are believed infected.

Globally, more than 1,400 people are sick and more than 50 have died from SARS, which scientists believe is a new form of a virus that causes the common cold. Deaths also have occurred in mainland China, Vietnam and Canada. In the United States, there are 59 suspected cases and no deaths.

The disease has spread mostly among health care workers.