A team of South Korean scientists says it has succeeded in extracting human embryonic stem cells from frozen embryos.

Park Se-pill, head of Maria Biotech, said his research team extracted seven cell lines from eleven inner cell masses, using 20 donated frozen embryos, which were thawed for research purpose.

Park said his team's extraction rate of more than 63 percent is over five times the rate hitherto achieved, which generally ranged between 10 and 36 percent.

The breakthrough is being hailed as a feat that could sidestep ethical and religious controversies surrounding the use of human embryos in stem cell research.

Park's research results were published in the March edition of the British scientific journal, Human Reproduction.

The announcement of the research came on the heels of the recent cloning of human embryos and extracting of embryonic stem cells by another team of South Korean scientists led by Hwang Woo-suk.