The United States was not aware that South Korea's president intended to declare martial law, U.S. Secretary of State Antony Blinken told Reuters on Wednesday, adding that he anticipated speaking to his South Korean counterpart in the coming days.

Officials from the White House, Pentagon and State Department all said they were in close contact with their South Korean counterparts as they assessed the situation.

South Korean President Yook Suk Yeol’s failed imposition of martial law could hurt the trilateral security cooperation among the U.S., Japan and South Korea, experts say.