North Korea appears to have deployed soldiers and weapons to guard posts near the border that were shut in a 2018 deal with South Korea as tensions between the neighbors ratchet up in the wake of Pyongyang’s recent spy satellite launch.

South Korean military officials spotted activity near the posts inside the Demilitarized Zone last week using cameras and thermal imagery, Yonhap News Agency reported Monday. Yonhap also released images provided by the Defense Ministry that it said showed a handful of soldiers outside of a small post inside the DMZ.

North Korea had detonated 10 of 11 guard posts inside the DMZ in the wake of a summit about five years ago between leader Kim Jong Un and then-South Korean President Moon Jae-in that led to an agreement to reduce tensions along the heavily fortified DMZ dividing the peninsula.

Current President Yoon Suk Yeol, a conservative, has been skeptical about the deal struck by his predecessor, who advocated rapprochement with Pyongyang. Yoon’s government last week suspended part of the 2018 agreement after North Korea put the spy satellite in orbit, with Seoul resuming reconnaissance flights near the border that were suspended under the agreement.

North Korea then announced it intended to scrap the entire accord.

After two failed tries this year, Kim’s regime last week launched a rocket that put a spy satellite into orbit. While North Korea has hailed the latest mission as a success, there have been no indications from the outside world about whether the probe is actually operational.

Although officials in Seoul believe a North Korean spy satellite would be rudimentary at best, it could help Pyongyang refine its targeting as it rolls out new missiles designed to deliver nuclear strikes in South Korea and Japan, which host the bulk of America’s military personnel in the region.