Fearful that the SARS virus could spread farther, China on Sunday urged people not to travel during one of the nation's biggest celebrations -- the weeklong May 1 International Workers' Day holiday.

"The purpose of such an act is to prevent the massive movement of people and the possible spread of the disease," Gao Qiang, a executive vice health minister, told reporters.

China on Sunday reported a marked increase in SARS deaths and cases, saying that 12 more people have died and that the number of infections in Beijing has soared to 339 -- a near tenfold increase.

The new numbers raised China's total number of deaths to 79 and its cases to 1,807.

Gao acknowledged that the travel advisory could deal a big blow to China's economy. The long holiday usually boosts the economy with a wave of domestic spending.

"I'm sure this measure will mean massive loses in tourism revenue, but people's lives and health had to be put above everything," Gao said.

The Health Ministry also issued a special advisory to university students, urging them not to travel during the holiday.

China has been accused of covering up SARS cases, and the nation's top leaders have recently begun demanding timely and honest reporting from local officials.

Gao acknowledged that there have been problems. "The ministry of health was not well prepared against an outbreak of a public health threat," he said.

"It has not given out clear instructions or effective guidance," he said.

Severe acute respiratory syndrome was first reported in China's southern Guangdong province in November.

Gao provided a detailed breakdown of the places in China that have reported deaths and cases as of April 18. The statement said that 46 people have died in Guangdong, and 18 have died in Beijing, where 339 cases have been reported.

The central province of Shaanxi had 108 cases, while the northern territory of Inner Mongolia has 25 cases, the statement said. In the south, Guangxi had 12 cases, Hunan six, Fujian three and the commercial center of Shanghai two.

In central Chinese provinces, Henan reported two cases while Hunan had six. The southwestern province of Sichuan had five cases, the document said.