WASHINGTON — A senior U.S. official said Tuesday the requirements for the transfer of wartime operational control (OPCON) to South Korea remain unchanged but stressed that the threat environment on the Korean Peninsula was evolving faster than ever before. "The fundamental requirements for OPCON transfer have not changed. But the threat environment is evolving faster now than ever before," the official told Yonhap News Agency in response to a media inquiry on the state of the bilateral OPCON transition review process. "Together, we must be prepared to deter and defeat all regional threats to the alliance," the official, who asked not to be identified, added. The official appeared to reflect concerns over evolving threats posed by advancements in Pyongyang's missile and nuclear programs. Separately, the Pentagon reaffirmed that the transfer of wartime OPCON to South Korea remains a conditions-based process agreed upon by Washington and Seoul, stressing that the necessary requirements must be met before any transition takes place. "The transition of wartime OPCON remains a conditions-based