North Korean state media announced that authorities have detained two South Korean citizens on charges of espionage. North Korea’s Korean Central News Agency identified the two men as Kim Kuk Gi and Choe Chun Gil. Both reportedly were based in the northeastern Chinese city Dandong, which borders North Korea.

Reuters is reporting that the news agency also published photos of the two South Koreans speaking at a news conference in the North Korean capital of Pyongyang, where they read statements detailing their alleged crimes. During the news conference the two were accused of being employed by Seoul’s National Intelligence Service and running an underground religious group where Kim was involved in “propaganda,” which likely means they believe he worked to bring foreign information and media into the pariah country through its porous borders and black markets.

State media said one of the two “spies” used USB drives and SD cards to sneak information into the country from Dandong. Dandong is known as an economic hub for North Korean businesses and is often referred to as the source of outside goods entering the country because of ease of accessibility between North Korea and China, as opposed to the Demilitarized Zone (DMZ) separating North Korea and South Korea.

“They zealously took part in the anti-DPRK smear campaign of the U.S. imperialists and the puppet group of traitors to isolate and blockade the DPRK in [the] international arena,” the North Korean report said. “[Kim and Choe] were unmasked and arrested while committing espionage ... [They] are the heinous terrorists who worked hard to do harm to the supreme leadership of the DPRK.”

The South Korean intelligence agency has not made any statements on the claims made by Pyongyang or the affiliation of the two detained men.