North Korea has sent troops to its southern border to restore guard posts taken down under a 2018 agreement with South Korea, Seoul’s military said on Monday, after Pyongyang’s launch of a spy satellite stoked tensions on the peninsula.

In response to the launch last week, Seoul partially suspended the agreement that was aimed at easing border hostilities, prompting Pyongyang to scrap the pact entirely and warn it would “never be bound” by the deal again.

A South Korean military official told Agence France-Presse (AFP) on Monday that Pyongyang had recently sent armed personnel and equipment to restore the guard posts.

The Yonhap News Agency reported that North Korean soldiers were “seen rebuilding the guard posts from Friday,” said a military official, and that all 11 posts withdrawn under the five-year-old deal were expected to be restored.

One photo released by South Korea’s military shows four North Korean soldiers rebuilding a wooden guard post in the Demilitarized Zone that separates the two countries.

North Korea’s accelerated development of its weapons programs has alarmed Seoul.

South Korea deployed “surveillance and reconnaissance assets” to the border after the satellite launch, in what its military said was an “essential measure” to defend against the North’s growing threats.

In response, Pyongyang said it would “deploy more powerful armed forces and new-type military hardware in the region along the Military Demarcation Line” between the two Koreas.

Nuclear-armed North Korea is barred by successive rounds of United Nations resolutions from tests using ballistic technology, and analysts say there is significant technological overlap between space launch capabilities and the development of ballistic missiles.

Last week’s launch of the “Malligyong-1” was Pyongyang’s third attempt at securing a military eye in the sky after two failures in May and August.

The launch drew condemnation from the international community, including the United States and South Korea, for its “destabilizing effect on the region.”

Pyongyang said its launch was a “legitimate and just exercise of the right to self-defense,” said a Foreign Ministry statement run by the official Korean Central News Agency (KCNA) on Monday.

Successfully putting a spy satellite into orbit would improve North Korea’s intelligence-gathering capabilities, particularly over the South, and provide crucial data in any military conflict, experts say.

In a visit to the Pyongyang space control center on Monday, North Korean leader Kim Jong Un expressed “great satisfaction” at the preparations for the satellite’s reconnaissance mission that will begin on December 1, the KCNA said in a separate report.

Kim also reviewed a batch of satellite photos of the US Anderson Air Force Base in Guam received at 9:17 a.m., as well as photos of the Italian capital Rome, it added.

It is the latest in a series of North Korean reports purporting Kim has reviewed satellite imagery, though Pyongyang has not publicly disclosed it.

The North previously claimed, within hours of the launch, that Kim was shown photos of US military bases in Guam taken by the satellite.