In a stunning move that could further upend already fraying ties between Japan and South Korea, Seoul on Thursday announced that it would scrap a key intelligence-sharing pact with Tokyo, with the South’s presidential Blue House saying in a statement that it did not meet Seoul’s “national interests” to maintain the deal amid the intensifying spat between the two neighbors.

Citing a “grave change” in security cooperation conditions that it attributed to the recent strengthening of export controls by the Japanese government, the Blue House said it planned to inform Tokyo of the move to end the General Security of Military Information Agreement before a Saturday deadline, the South’s Yonhap news agency said.

Kim You-geun, deputy director of South Korea’s presidential national security office, said this would be done via a diplomatic channel.

South Korea’s decision is “extremely regrettable,” a Japanese government source was quoted as saying by Kyodo News. Tokyo also lodged a protest against Seoul over the scrapping of the pact between them, NHK reported.

The U.S. Defense Department, meanwhile, urged the two two allies to come together to repair their relations.

“We encourage Japan and Korea to work together to resolve their differences,” Pentagon spokesman Lt. Col. Dave Eastburn told The Japan Times. “I hope they can do this quickly. We are all stronger — and Northeast Asia is safer — when the United States, Japan, and Korea work together in solidarity and friendship. Intel sharing is key to developing our common defense policy and strategy.”

The pact, inked in November 2016, allows the two U.S. allies to share sensitive information on missile threats from North Korea, among other things. It is automatically renewed annually unless one of the countries decides to pull the plug.

Seoul had initially been expected to extend the pact, given the importance of military cooperation between the United States, South Korea and Japan.

Tokyo-Seoul ties have been highly strained recently over trade and historical issues. South Korea’s Supreme Court last year ordered Japanese firms to pay compensation for wartime forced labor.

Tokyo, meanwhile, has introduced new export control measures on key materials desperately needed by top South Korean semiconductor-makers, citing”loss of trust” and security concerns without providing specific evidence for the decision.

Japan has denied the two matters are linked but the change fueled emotional confrontations between the two countries, sparking boycott campaigns against Japanese products in South Korea.

Japanese officials had said they had hoped to extend the intelligence-sharing pact, pointing to its importance in enhancing the trilateral alliance between Japan, South Korea and the United States.

“GSOMIA has been instrumental in strengthening defense ties between South Korea and Japan, and has been renewed since its enactment in 2016 under the understanding that it contributes significantly to the peace and stability of the region,” Chief Cabinet Secretary Yoshihide Suga said in a news conference earlier in the day.

“We understand that the current relationship between South Korea and Japan is very fraught. Regardless, it is important to continue working together in areas that require collaboration,” he added.

The decision comes amid ramped-up missile launches and weapons tests by nuclear-armed North Korea, and was likely to upset ties with the two Asian nation’s top ally, the United States.

In an apparent bid to reassure Washington amid the downturn in ties, South Korean Foreign Minister Kang Kyung-wha said Thursday that Seoul’s decision to terminate the pact was “separate” from its security ties with Washington.

“(The decision) is a separate issue from the South Korea-U.S. alliance, and the alliance will incessantly strengthen cooperation,” the Yonhap news agency quoted Kang as saying.

U.S. President Donald Trump had called for improved relations between the two earlier this month, saying heightened tensions between them put the United States in a “bad position.”

“South Korea and Japan are fighting all the time. They’ve got to get along because it puts us in a bad position,” Trump said at the time. “They’re supposed to be allies.”

Under the agreement, Tokyo and South Korea have exchanged sensitive military intelligence, including data about North Korea’s missile launches, rather than going through Washington, which has separate intelligence-sharing deals with both allies.

While South Korea mainly provides Japan with human intelligence via spies, defectors and other sources, as well as intelligence detected from near inter-Korean border areas, Japan has a technological advantage with its cutting-edge reconnaissance capabilities, operating military satellites, radar and surveillance aircraft.

The passage of the agreement in 2016 received high praise from then-U.S. President Barack Obama, as it signified major progress toward Washington’s long-cherished goal of U.S.-South Korea-Japan trilateral security cooperation.

Stephen Nagy, a senior associate professor of international relations and politics at the International Christian University in Tokyo, said the decision by Seoul would only serve South Korean President Moon Jae-in’s political interests.

“Seoul’s decision to end the GSOMIA agreement serves no purpose except to win political points for the Moon administration,” Nagy said.

“Ending the agreement would handicap needed cooperation on North Korea, weapons proliferation, trilateral U.S.-Japan-ROK coordination on the peninsula and in terms of managing effectively China’s reemergence as the regional hegemon,” he said using the acronym for the South’s formal name, the Republic of Korea

For Japan, he said, “it sends a strong signal that the ROK is an unreliable partner in the region. It will compel Japan to strengthen Japan-U.S. relations as well as relations with Australia, India and other partners.

“For Japan-ROK relations, this is another wound in an increasingly politicized relationship that will damage security, business and other forms of cooperation.”