BEIJING (AP) — Swine flu is spreading in China from cities into rural areas, and from the coast inland, a health ministry official said Friday. Incidents of large-scale group infections are also replacing isolated ones, said Liang Wannian, deputy director of the Health Ministry's emergency office. So far, China has not been hard hit by swine flu. Out of a population of 1.3 billion people, it has reported a total of 6,968 cases as of Thursday, with all 31 provinces having infections. No deaths have been reported. But Liang said the virus is spreading at a quicker rate because of the arrival of autumn and the start of school terms, with more than 100 cases reported every day. "The situation we face in controlling the virus is not optimistic," Liang told reporters, according to a transcript of the news conference. Domestic transmission of the virus has also surpassed cases caught from overseas, making up 94.8 percent of new infections, he said. The number of domestic cases increased by 3,696 from Aug. 24 to Sept. 10, he said. Since the World Health Organization declared swine flu a pandemic in June, pharmaceutical companies have been racing to produce a swine flu vaccine and many countries have planned mass vaccination campaigns beginning in October. Chinese officials approved a vaccine last month they say prevents the new flu in a single dose. Liang said the country has also prepared enough Tamiflu for 10 million people. Last month the WHO said while production was on track, the viruses being used to make the vaccine were growing slowly, which would limit global supplies.