North Korea has detained a US citizen on suspicion of “hostile acts” against the regime, the state-run Korean Central News Agency reported Sunday.

The regime described Kim Hak-song as “a man who was doing business in relation to the operation of Pyongyang University of Science and Technology.” KCNA said the American was detained Saturday, but did not release more details on his alleged crime.

“The relevant authority is currently carrying out a detailed investigation into the crime of Kim Hak-song,” the state-run news agency said.

A State Department official told CNN the US is “aware of reports” that an American citizen was detained.

“When a US citizen is reported to be detained in North Korea, we work with the Swedish Embassy in Pyongyang, which serves as the United States’ Protecting Power in North Korea,” the official said. “Due to privacy considerations, we have no further comment.”

Kim Hak-song is believed to be the fourth US citizen currently detained in North Korea.

In April, KCNA said Tony Kim — also known as Kim Sang Duk — was detained for “hostile acts” toward the North Korean regime.