Three officials who had approved and conducted a joint China-US test of genetically-modified (GM) rice on school children in central China's Hunan Province had been sacked, authorities said on Thursday.

The officials were punished for "violating relevant regulations, scientific ethics and academic integrity," according to a statement jointly released by the Chinese Center for Disease Control and Prevention (China CDC), Zhejiang Academy of Medical Sciences (ZAMS), and Hunan provincial CDC.

The three institutions said in the statement that they are "deeply sorry" about the negative impact caused by this test which was jointly conducted by Chinese and American researchers.

The officials punished include Yin Shi'an from China CDC, Wang Yin from ZAMS and Hu Yuming from Hunan provincial CDC.

Yin Shi'an, China CDC's National Institute of Nutrition and Food Safety's maternity and child nutrition office director, was removed from his post, according to the statement.

The institute disqualified him from any scientific research within a period of three years, and revoked his title as a doctoral mentor.

Wang Yin, a section chief of ZAMS, was sacked by Zhejiang provincial health authority.

Yin and Wang were punished for failing to inform the school children and their parents of the fact that the rice was genetical-modified, and concealing the truth from relevant authorities and the school, according to the statement.

Wang was also punished for abuse of power as she approved the research as ethical in the name of ZAMS without authorization.

The ZAMS disqualified Wang for professional ranking promotion and dismissed her from its academic board and ethics committee. Wang also received a disciplinary warning from the academy's Party committee.

Hu Yuming, an official of the Hunan provincial CDC, was removed from office for failure in supervision and dereliction of duty and was warned by the Party committee of the provincial CDC, the statement said.

Greenpeace first disclosed the test in late August, saying that researchers fed "Golden Rice", which is genetically-modified to be rich in beta carotene, to 25 children aged between six and eight in Hunan.

The Ministry of Health later ordered China CDC to investigate whether dozens of children in Hunan were used as GM food test subjects.

Greenpeace discovered the test from a paper published in the August edition of The American Journal of Clinical Nutrition which claimed that "Golden Rice" is effective in providing Vitamin A to children.

The research approved by the National Institutes of Health of the United States in December 2002, was led by Tang Guangwen, director of the Carotenoid and Health Laboratory of Tufts University in the United States. It was intended to explore ways in preventing deficiency of Vitamin A among children.

Tang conducted the research in cooperation with Yin and Wang.

China CDC discovered that the test was conducted in 2008 on 80 pupils in Hengnan County of Hunan Province, with 25 of them each being fed 60 grams of Golden Rice on June 2.

According to the statement, Tang cooked the "Golden Rice" in the US and brought the cooked rice to China on May 29, 2008 without due declaration to relevant Chinese authorities.

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

Prior to the test, the research team held a meeting to brief the children's parents or guardians, but did not tell the parents that the test would be using GM food.

The team handed out only the last page of informed consent forms to the children's parents and guardians and asked them to sign on the page which had no word referring to "Golden Rice", nor about the fact that the rice fed to the children was a kind of GM food, according to the statement.

After the test, in July 2008, Chinese authorities conducted an investigation on the researchers as they learned that a US university was conducting "Golden Rice" test in China. However, the researchers lied that the test had not started yet.

During this year's investigation, Yin and Wang "concealed main facts and provided false information, severly disturbing the probe," the statement said.

The China CDC also dispatched investigators to the US. Evidence collected from Tufts University and the NIH consolidated the above-mentioned findings, the statement said.

According to Tufts University, the ethic review of each research has to be renewed annually, however, Tang started the test in Hunan before the yearly renewal was completed. Tufts is now investigating the case on suspected ethical violations.

Food safety experts claimed the "Golden Rice" to be harmless to health, but the test, since disclosed by Greenpeace, stirred panic among parents of tested children and caused public uproar.

Xu Haibin, researcher with China National Center for Food Safety Risk Assessment, said that the "Golden Rice" only differs from non-GM rice in that it has a higher amount of beta carotene, and so far there is no proof that "Golden Rice" is harmful to people's health.

Xu also said nor is there any proof that eating 60 grams of "Golden Rice" is harmful to children aged between six to eight.

However, the parents panicked upon knowing their children had been fed GM rice. Rumors online said that those who ate "Golden Rice" would become impotent.

A father surnamed He told Xinhua, that his child, after learning the rumors from the Internet, comforted him and his wife, "Papa, mama, don't worry, I can adopt a baby when I grow up."

Yin Shi'an told Xinhua, "I didn't think much, and I just wanted to finish the research."

According to a statement issued by the MOH, the "Golden Rice" test shows that some researchers lack awareness of law or scientific ethics, and some research institutions practice poor supervision over science projects.