The World Heath Organization (WHO) has apologized to the Chinese government after bird flu samples provided by China were misused by foreign research institutions, China's chief veterinarian Jia Youling revealed here Friday.

"Mr. (Henk) Bekedam from the WHO Beijing office apologized to me personally twice. His attitude was very sincere and I was deeply moved", Jia told a press conference hosted by the information office of the State Council, China's cabinet.

Jia, director of the Ministry of Agriculture's veterinary bureau, said China provided five bird flu samples to the WHO in June 2005, at the WHO's request, after a major outbreak in 2004.

"Foreign research institutions improperly used the samples in two cases, violating the intellectual property rights of Chinese researchers," he said.

In one research paper, the samples were attributed to countries other than China, Jia said, adding that co-author Rob Webster, from St. Jude Children's Research Hospital in the United States, had also apologized to the Chinese research institution concerned.

In another case, foreign researchers cited the Chinese sample without giving credit to the Chinese side, which contravenes international practice, Jia said. Jia declined to give the researchers' names.

Jia rejected accusations that China has been reluctant to share its bird flu samples with the international community.

In addition to the five samples provided in 2005, he said China has provided WHO with 20 further samples this year.

He said the provision of the 20 samples took several months because of strict, time-consuming procedures on both sides. Great caution was needed to handle dangerous bird flu samples.

Jia said the Ministry of Agriculture will continue to work closely with the international community, including the WHO, to control bird flu.

Xinhua reporters were unable to reach WHO's Beijing office for comment. But previously Bekedam told Reuters that the Chinese samples were used in research that failed to acknowledge that China's Ministry of Agriculture had identified the virus, in breach of scientific protocol.

"That happened twice, and I apologized on behalf of the WHO collaborating center because that is bad behavior among scientists," he said.