WASHINGTON -- The planned transition of the wartime operational control (OPCON) of South Korean troops will take place when all necessary conditions are met, not because of a simple passage of time, a Pentagon spokesperson said Thursday.

John Supple also said a "conditions-based" transition is not only what has been agreed on but also what is necessary to ensure peace and security.

"Wartime Operational Control will transition when the mutually-agreed upon conditions are fully met," Supple said when asked if there may be any change in OPCON transition under the new US administration of Joe Biden, who took office last Wednesday.

South Korea has pushed to regain OPCON before President Moon Jae-in's term ends in May 2022, but such chances have increasingly looked unlikely amid views that more time is necessary for Seoul to meet the agreed-upon conditions amid the COVID-19 pandemic.

"A conditions-based wartime OPCON transition is not only what the United States and Republic of Korea mutually agreed to, it is also necessary to ensure the security of our military forces, peoples, and the region," Supple told Yonhap News Agency in an email.

"A commitment to a specific timeframe would put our forces and people at risk," he added. "Similarly, ensuring the security of military forces, peoples, and the region requires is more complicated than merely swapping the leadership of the Combined Forces Command."

South Korea retook the peacetime OPCON of its troops in 1994. (Yonhap)