U.S. President Joe Biden, center, meets with the Republic of Korea President Yoon Suk-yeol, left, and Japan's Prime Minister Fumio Kishida, right, during the NATO summit in Madrid on June 29, 2022. The White House national security adviser Jake Sullivan, Secretary of State Antony Blinken, Secretary of Defense Lloyd Austin and National Security Council Director for the Korean Peninsula and Mongolia are sitting behind Biden. SUSAN WALSH AP MADRID The leaders of the United States, the Republic of Korea and Japan expressed deep concern over missile tests by the Democratic People's Republic of Korea and said they would cooperate more closely to address the issue.
US President Joe Biden, Japanese Prime Minister Fumio Kishida, and ROK President Yoon Suk-yeol met on the sidelines of the NATO summit in Madrid.
The DPRK has been conducting missile tests at an unprecedented pace this year.
The three leaders agreed to explore further ways to strengthen deterrence against the DPRK along with security cooperation.
The deterrence capabilities of the Japan-US and US-Republic of Korea alliances need to be upgraded as part of the effort to strengthen the trilateral partnership between Japan, the US, and ROK, Kishida said.
The ROK and Japanese leaders are attending NATO's annual summit as observers for the first time.
Ties between Japan and the ROK have been strained for a long time because of the memories of Japan's occupation of the Korean Peninsula from 1910 to 1945.
READ MORE: DPRK says Biden govt took the wrong first step'' over the latest missile test.
Relations deteriorated to their worst in years under the previous ROK President Moon Jae-in, with spats over territory and history and the two nations calling for an intelligence sharing pact. Yoon has expressed a desire to repair ties, and Kishida has seemed to respond favorably.