Cloning pioneer Hwang Woo-seok is about to surprise the world again.

Local scientists on Thursday said he will fly to the United States later this month to publish his latest research in the journal "Science."

The Seoul National University professor's findings are under tight secrecy.

Experts predict he will announce successful pre-clinical tests of stem cells extracted from a cloned human embryo.

Successful trials are expected to greatly assist the fight against terminal diseases.

Last year, Hwang performed the world's first stem cell extraction.