Parents whose children unknowingly took part in a study involving genetically modified rice in Hunan province have received compensation but said they are more worried about their youngsters' health.

Each of 25 families, whose children were fed 60 grams of the GM food "golden rice" in the study, received 80,000 yuan ($12,800) on Friday from local government authorities.

The study, which covered some 80 children then aged between 6 and 8, was conducted in a primary school in Jiangkou township, Hengnan county, in 2008.

"Compared with the compensation, I have more concerns over possible health hazards to my child," said Xie Xiaohua, whose 11-year-old daughter, Liao Ke, was included in the study.

The girl developed dizziness and fever shortly after the test, Xie said.

"We were not told before the test by relevant authorities that it was genetically modified rice. We were only asked to sign names and we thought it was a nutrition program," Xie told China Daily.

Investigations by health authorities show the research team told parents about the experiment but did not say GM rice would be used.

Xie said local authorities have not announced the names of the 25 children.

Authorities in Hengnan county have promised to take full responsibility if children suffer health problems as a result of the test.

Another mother, who gave her name only as Luo, told the Beijing News the local government will soon arrange for all children involved in the study to have medical checks.

"I signed the compensation agreement with the government on Dec 1. I would rather not have received the money. So far, I don't know how dangerous the "golden rice" will be to my child's health," said Luo, whose daughter was fed the GM food.

Three officials who approved and conducted the controversial test have been sacked, the Chinese Center for Disease Control and Prevention said on Thursday.

The officials are Yin Shi'an, from the center: Wang Yin, from the Zhejiang Academy of Medical Sciences: and Hu Yuming, from the Hunan Center for Disease Control and Prevention.

US-based Tufts University, which jointly organized the study, is aware of the announcement made by the Chinese health authorities.

"While we respect China's review process which led to the statement, it would be inappropriate to make further comments at this time as investigations are currently under way in the United States," Andrea Grossman, assistant director of public relations at the Massachusetts-based institution, was quoted as saying by Xinhua News Agency.

Grossman said the university launched a full review in August to determine if proper study procedures were followed. This was after becoming aware of questions about the "golden rice" study, raised after the test was disclosed by environmental group Greenpeace.

"We have also been cooperating with Chinese investigators engaged in their own review. We will continue to cooperate with China's authorities on this matter," Grossman said.

According to the Chinese statement, Guangwen Tang, director of the Carotenoids and Health Laboratory of Tufts University, cooked the GM rice in the United States and brought it to China on May 29, 2008, without declaring it to the Chinese authorities.

Four days later, Tang and other research participants re-cooked the rice, mixed it with ordinary rice and served it for the children's lunch.

The central government introduced a regulation in 2001 to ensure the safety of GM food, with strict provisions for research, testing, production and marketing such products, according to Xinhua.

The regulation states that those conducting GM agricultural experiments should have certain qualifications, and form a panel to oversee the safety of the experiments.

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