A U.S. scientist is trying to distance himself further from an embattled South Korean scientist whose work on human cloning has come under increasing scrutiny.

Gerald Schatten of the University of Pittsburgh is asking Science magazine to remove his name from a report written by Hwang Woo-Sok. The report detailed his work in creating the world's first patient-specific stem cells.

Mr. Schatten now says he doubts the study's accuracy, and adds that he has received allegations that "certain elements" may have been falsified.

Last month, he withdrew from a stem cell project led by Mr. Hwang after ethical allegations surfaced involving the Korean's pioneering work in cloning human embryos to extract embryonic stem cells.

Several leading researchers are calling on Mr. Hwang to submit his work for an independent analysis.

Some information for this report provided by AP and Reuters.