South Korea’s military on Monday warned North Korea not to go ahead with its planned spy satellite launch, suggesting that Seoul could suspend an inter-Korean agreement to reduce tensions and resume front-line aerial surveillance in response.

North Korea failed in its first two attempts to put a military spy satellite into orbit earlier this year and didn’t follow through with a vow to make a third attempt in October. South Korean officials said the delay was likely because the North was receiving Russian technology assistance and that a launch could happen in the coming days.

“Our military will come up with necessary measures to protect the lives and safety of the people, if North Korea pushes ahead with a military spy satellite launch despite our warning,” Kang Hopil, a senior South Korean military officer, said in a televised statement.

Seoul’s Defense Minister Shin Wonsik said in an interview with public broadcaster KBS on Sunday that the launch was expected later this month, and that South Korean and United States authorities were monitoring Pyongyang’s moves.

The United Nations Security Council bans any satellite launches by North Korea because it views them as a disguised test of its missile technology. Kang said that while Pyongyang needed a spy satellite to improve its monitoring of South Korea, the launch was also aimed at bolstering its longrange missile program.

Foreign governments and experts say North Korea is seeking Russian technologies to enhance its nuclear and other military capabilities in return for supplying conventional arms to support Russia’s war on Ukraine.

Both Moscow and Pyongyang have dismissed as groundless the alleged arms transfer deal, but both nations — locked in separate, protracted tensions with the US — have been openly pushing to expand their cooperation in recent months.

In September, North Korean leader Kim Jong Un traveled to Russia’s Far East to meet President Vladimir Putin at the Cosmodrome, Russia’s most important domestic space launch center.

When Putin was asked by Russia’s state media whether Moscow would help Pyongyang build satellites, he said “that’s why we have come here. The [North Korean] leader shows keen interest in rocket technology.”

Shin said that, with the likely help of Russia, North Korea appeared to have almost overcome an unspecified engine problem on a rocket needed to send a spy satellite into space.

The North, he added, is likely to launch the satellite before November 30, when South Korea plans to launch its first military spy satellite from California’s Vandenberg Air Force Base.

Kang didn’t explicitly say what retaliatory steps South Korea could take if the North attempts a third launch. But he strongly hinted the steps could include a resumption of aerial surveillance activities and live-fire drills at border areas, in breach of the 2018 inter-Korean military agreement on easing front-line tensions.

He asserted that North Korea has already violated the agreement numerous times. He cited Pyongyang’s destruction of an unoccupied inter-Korean liaison office in the North, flying of drones into South Korea, and live-fire drills along the western maritime boundary.

“Despite the North’s repeated violations of the agreement, our military has been patiently abiding by clauses in the military agreement, but that has caused considerable problems in our military’s readiness,” Kang said.

He said South Korea’s aerial reconnaissance designed to monitor North Korea’s forward-deployed artillery guns has been significantly restricted by the 2018 deal.

He said South Korean military units on border islands had been unable to conduct live-fire drills in their areas and instead held the exercises in faraway inland firing ranges.

The military deal, reached during a short-lived rapprochement between South Korea’s liberal then-president Moon Jae-in and Kim, created buffer and no-fly zones along the rivals’ border. The Koreas also removed some of their front-line guard posts and land mines.