Former Khmer Rouge leader Khieu Samphan was moved from a Phnom Penh hospital to his holding cell at the tribunal Thursday afternoon, officials said.
"He is now back in the detention facility," tribunal spokesman Peter Foster said. "He has been released from the hospital. Clearly, at the hospital, they determined that he was stable and healthy enough to return to the detention facility."
A tribunal statement said he was brought from the hospital at 3:30 pm Thursday, following observation from specialists.
Khieu Samphan's lawyers were quoted in media reports this week saying his condition was worsening, following his admittance to Calmette hospital May 22.
But Khieu Samphan's wife, So Socheat, said earlier Thursday he had improved "gradually" since his admission for high blood pressure.
Lawyer Sy Bory said earlier Thursday that even if his client's condition improved, he should not be immediately sent back to detention.
Khieu Samphan, who was the nominal head of the regime, faces charges of war crimes and crimes against humanity.