South Korea said it would take action against North Korea for launching what it claims to be a spy satellite, potentially within the next week, in the starkest warning yet over what the South believes is a violation of UN Security Council resolutions banning missile tests.

At a briefing Monday, Kang Ho-pil, chief director of operations at the South’s Joint Chiefs of Staff, urged the North to immediately stop preparations for another launch after two previous failures this year.

“The launch is a clear breach of UNSC resolutions barring all tests using ballistic missile technology, and is a provocation threatening our national security,” Kang said. “We will pursue action to protect our people’s safety and security should the North fail to heed the warning.”

The announcement, coming a day after Defense Minister Shin Won-sik openly fixed Nov. 30 as the latest the launch could happen, did not detail the kind of measures to expect.

As floated many times by Shin, Monday’s statement suggested the South could suspend a 2018 inter-Korean military agreement. The deal calls for ceasing “all hostile acts” by creating a “no-fly zone” around the border and removing landmines and guard posts in the heavily fortified Demilitarized Zone.

Missile and drone launches by Pyongyang since 2020, Kang added, show the North is not serious about abiding by the pact.

But reversing the agreement is not something the military could decide on its own, a senior JCS official said, noting a discussion with the National Security Council would be necessary. The NSC meeting Monday reaffirmed readiness to respond to any North Korean provocation, alongside the US and Japan, without disclosing much further.

“Joint naval drills involving South Korea and the US could take place should North Korea launch a satellite,” another senior military official in Seoul said, noting the USS Carl Vinson aircraft carrier, set to make a stop at Busan this week, could participate in the exercises.

Military officials in Seoul believe a North Korean spy satellite would be rudimentary at best, given their assessment of the previous rocket failures. But an arms deal the North is accused of having sealed with Russia in return for weapon supplies to Moscow has alarmed Seoul and Washington.

According to a South Korean lawmaker briefed by the country’s spy agency earlier this month, North Korea has sent more than 1 million rounds of artillery to Russia for its war in Ukraine. The White House last month shared similar intelligence. Moscow and Pyongyang have denied the accusations.