BEIJING - China will start vaccinating citizens against swine flu in coming weeks to fight a surge in cases that is expected to gain speed, the county's top health official said Tuesday.

Health Minister Chen Zhu said that performers in the Oct. 1 National Day parade will be the first group to be vaccinated. He did not go into details, but officials have earlier said the celebration to mark 60 years since the founding of the communist republic will involve 200,000 people, mostly soldiers and students.

Chen said the fall and winter flu season and the reopening of schools after the summer break presented challenges for the prevention of swine flu, known as H1N1, in the world's most populous country.

"We are faced with a grim situation," Chen told reporters. He added that data from the country's flu monitoring network showed that the virus "has already taken root in some groups of people."

Chen said cluster outbreaks of swine flu have surged rapidly, with 128 such reports since the end of June, and cases have been accelerating further since the start of this month, when schools reopened. Chen said 5,592 cases of swine flu have been reported on the mainland, with no deaths.

Since the World Health Organization declared swine flu to be a pandemic in June, pharmaceuticals have been racing to produce a swine flu vaccine and many countries have planned mass vaccination campaigns beginning in October. Last month, the agency said that while production was on track, the viruses being used to make the vaccine were growing slowly, which would limit global supplies.

China's vaccine production capacity is unable to make enough doses to cover everyone in the country of 1.3 billion people, so health authorities plan to focus on protecting students aged 5-19 and people suffering chronic respiratory and cardiovascular diseases, Chen said.

Other vulnerable groups being considered include pregnant women and health care workers as well as border control officers, rail workers, soldiers and police, he said.

China's drug regulator last week approved two domestically made swine flu vaccines after manufacturers completed clinical trials that showed one shot of vaccine is effective on people ages 3 to 60. One of the drug makers said the government has ordered 3.3 million doses of its swine flu vaccine for delivery before Sept. 15.