The World Stem Cell Hub says it will follow international ethical standards in pursuing its research.

The hub's planning director Sung Myung-whun said in a Tuesday news conference that though scientists abroad understand, many are critical of the ethical lapses committed by Hwang Woo-suk's research team.

Meanwhile, Hwang's research partner Ahn Kyu-ri returned to Seoul after visiting the United States and Japan for talks with overseas institutes on stem cell research, but declined to appear at the news conference.

Sung said the hub will team up with institutes abroad to meet global ethics governing stem cell research.

He declined comment on the report that American researcher Gerald Schatten asked for half of the patent rights in Hwang's research and that Schatten called Hwang's research phony.

Sung also denied that Schatten requested the chairmanship of the hub's board of directors, saying no discussion has been held since the board has yet to be formed.

Sung said the hub will leave Hwang's seat vacant and will ask him to return once he resumes work.

The hub will also hold regular news briefings on its operations.