Prosectors are seeking jail time for former stem cell researcher Hwang Woo-suk. (Associated Press/Lee Jin-man)

Prosecutors demanded a four-year prison term Monday for a South Korean scientist disgraced in a cloning scandal that shook the international scientific community, and led to his trial on fraud and other charges.

Hwang Woo-suk was fired from the prestigious Seoul National University after purported breakthroughs — including the claim of producing a human embryo through cloning and recovering stem cells from it — were deemed bogus in 2005, when a key paper was found to contain fake data.

Once hailed as a national hero, Hwang is accused of accepting funds under false pretenses, embezzling and illegally buying human eggs for his research, charges related to the fake claims.

Prosecutors sought the four-year prison term during a hearing at the Seoul Central District Court. Hwang was present in the packed courtroom, and supporters greeted his entrance with applause.

"The people's disappointment was very serious because their expectation for his stem cell research had been high," an unidentified prosecutor told the courtroom.

He said Hwang tarnished South Korea's image abroad and that prosecutors saw the case as a chance to "resolve chronic research fraud in the academic field."

Hwang pleaded for leniency, saying if the court forgives him, he is ready to "pour the last of my passion" into research.

Sentencing expected Oct. 19

The court will rule on his guilt or innocence, and decide a sentence Oct. 19, according to Yonhap news agency.

Hwang had been the only South Korean scientist allowed to carry out research into stem cells — master cells that can grow into any bodily tissue — that scientists say could lead to revolutionary cures for hard-to-treat diseases such as Alzheimer's. But the government stripped him of his licence in 2006, citing his "ethical problems."

That case scandalized the international scientific community and caused intense soul-searching in South Korea.

Hwang and his former colleagues at Seoul National University — South Korea's most prestigious — claimed in 2004 to have produced a human embryo through cloning and to have recovered stem cells from it.

A year later, Hwang said the team created human embryonic stem cells genetically matched to specific patients — a purported breakthrough that promised a way to withstand rejection by a patient's immune system.

But a university committee later declared the 2005 paper a fraud based on faked data, and cast doubt on his 2004 findings as well.

Hwang publicly apologized for faking data in the two papers, but claimed a fellow researcher switched his cell lines. Hwang, stripped of his right to carry out research on cloning human embryos, is now focusing on animal cloning at a local institute.

Though most of his research was found to be fake, Hwang and his team of scientists successfully created the world's first known dog clone in 2005, and that achievement was independently confirmed.