A Chinese man returning from studying at a U.S. university has become the first suspected case of swine flu in mainland China, the country's Health Ministry said on Sunday.

The ministry said the man, 30, took a flight from Tokyo and arrived in Beijing on Saturday before heading to the city of Chengdu in Sichuan province on the same day.

Officials did not specify where he studied.

The number of confirmed cases of the H1N1 infections across the globe rose Sunday by about 1,000 from the previous day, the World Health Organization said.

Twenty-nine countries have officially reported 4,379 cases of influenza H1N1, the WHO said.

Canada has reported 284 laboratory confirmed human cases, including one death, the Public Health Agency of Canada said Sunday. Among the provinces, British Columbia has the most cases with 79, followed by Ontario with 76.

The country has the third highest number of swine flu infections, but on Friday the United States overtook Mexico to become the country with the highest number of people with the illness.

By Sunday, the U.S. total was 2,254 cases, including three deaths. Mexico, which has been at the centre of the outbreak, was reporting 1,626 cases, including 48 deaths.

Japan confirmed its fourth case of swine flu Sunday in a teenager who recently returned from a school trip to Canada.

Three others in the group that visited Canada were earlier identified as having the virus.

With files from The Associated Press