North Korea appears to be using an old factory near its capital in order to build vehicles for nuclear missiles.

A joint investigation from the specialist outlet NK Pro and the James Martin Center for Nonproliferation at the Middlebury Institute found that a decades-old building near Pyongyang was the location of a secret manufacturing operation of transporter erector launchers (TELs).

It is thought that the production had been ongoing since November 2023, or possibly even earlier.

The launchers are believed to be designed for Hwasong-11D short-range ballistic missiles (SRBM) because they measure around 8.5 meters in length and 3 meters in width, according to the outlet.

North Korean Supreme Leader Kim Jong Un speaks during a press conference, June 19, 2024, in Pyongyang, North Korea, while Russian President Vladimir Putin visits the country for a two-day diplomatic visit. North Korea has... North Korean Supreme Leader Kim Jong Un speaks during a press conference, June 19, 2024, in Pyongyang, North Korea, while Russian President Vladimir Putin visits the country for a two-day diplomatic visit. North Korea has warned that American actions have forced it to “bolster” its nuclear arsenal. Contributor/Getty Images

Satellite imagery from Planet Labs reportedly shows around 49 thought-to-be TELs parked on a sports field at the Pyongyang building between November 8 and 9 last year. Some were reportedly removed about a week later, but 45 remained and weren't moved until early March. Some other vehicles spotted adjacent to the building were also moved in April.

No further possible TEL sightings were visible on the imagery, but the outlet noted there were long narrow objects laid out across several areas, suggesting the facility may still in have been use in June.

North Korea has warned that U.S. actions have forced it to "bolster" its nuclear arsenal, where the state-run news agency KNCA described the military relationship between the U.S., South Korea, and Japan as a "serious tripartite security crisis."

On August 4, North Korean leader Kim Jong Un handed over 250 new tactical ballistic missile launchers to the frontier military units of the border with South Korea at a ceremony, the state media KCNA WATCH reported.

NK News reported that the 250 TELs can carry four missiles, meaning potentially that up to 1,000 nuclear missiles now line the border, although the outlet writes that Pyongyang is not known to have acquired sufficient fissile material for such a high number.

According to NK News, the leader said the missiles are a new core weapon for the country's armed forces, while calling for the enhanced development of nuclear capabilities to fend off threats from the U.S.

One expert previously told Newsweek that North Korea has been sourcing missile components from the West, despite sanctions, and South Korea's former defense minister recently warned that Pyongyang's development of a nuclear weapon "is believed to be in the final stages."

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