The United States will impose additional sanctions next week against the Russian private military company Wagner Group, which US officials say helped the Russian military in the war in Ukraine, a senior administration official said on Friday.

The official, speaking on condition of anonymity, said the U.S. Treasury Department would designate the Wagner Group as a major transnational criminal organization.

“In coordination with this appointment, we will also next week impose additional sanctions against Wagner and his multi-continental support network. These actions recognize the transcontinental threat posed by Wagner, including through his ongoing pattern of serious criminal activity,” the official said.

The designation of Wagner’s group as a transnational criminal organization under US Executive Order 13581 freezes all US assets of the paramilitary company and prohibits Americans from providing funds, goods or services to the group.

“With these and other actions, our message to any company considering supporting the Wagner group is this: Wagner is a criminal organization that commits mass atrocities and human rights abuses, and we will work tirelessly to identify , destruction, exposure and targeting those who help Wagner,” the official said.

The White House said last month that Wagner’s group had taken over arms shipments from North Korea to help bolster Russian forces in Ukraine, in a sign of the group’s expanding role in the conflict.

The Ministry of Foreign Affairs of North Korea called the report baseless and condemned the United States for supplying Ukraine with lethal weapons. Last month, Wagner founder Yevgeny Prigozhin denied receiving weapons from North Korea and described the reports as “rumors and speculation.”

On Friday, the US government released a photo taken on November 18 that it said showed Russian railcars traveling between Russia and North Korea.