Experiments to verify the existence of so-called STAP cells should be conducted under strict monitoring, the head of a state-backed research center said amid growing doubts about discredited studies led by one of its researchers.

"It's necessary to ensure an environment in which misconduct absolutely cannot be allowed," Masatoshi Takeichi, director of Riken's Center for Developmental Biology said Thursday in a group interview. The center is the entity that hired beleaguered cytologist Haruko Obokata, who published two studies about a new type of stem cell that are due for retraction because of inconsistencies and allegations of research misconduct.

His remarks come after a panel of outside experts tasked with reforming Riken's operations called June 12 for the Kobe-based center to be immediately disbanded for failing to prevent misconduct by Obokata in connection with her papers on so-called STAP cells. STAP stands for "stimulus-triggered acquisition of pluripotency."