South Korea announced Thursday it is ending a military intelligence sharing agreement with Japan.
The General Security of Military Information Agreement (GSOMIA) signed with U.S. backing in November 2016, had been controversial in South Korea because of Japan's past colonization of the Korean Peninsula.
Amid Tokyo's toughened trade stance against South Korea this summer and weeks of souring relations between the two neighbors, speculation had been mounting that Seoul might decide to terminate the GSOMIA ahead of an Aug. 24 deadline.
Following a three-month notice period, the agreement will now formally expire in November.
Kim You-geun, deputy director of South Korea's presidential National Security Office, was quoted by local news agency Yonhap as blaming a "grave change in security cooperation circumstances between the two nations."
But a separate statement from Seoul's Defense Ministry insisted the South "will maintain a stable and perfect" combined defense posture with the U.S.
Washington's position on the sensitive northeast Asia region may have been weakened by South Korea's decision not to renew the GSOMIA because the U.S. enjoys key alliances with Seoul and Tokyo.