"We can confirm that North Korea has completed an initial arms delivery to Wagner, which paid for the equipment.
Last month, North Korea delivered infantry rockets and missiles into Russia for use by Wagner," the official said, speaking to Reuters on condition of anonymity.
The Biden administration on Wednesday unveiled new curbs on technology exports to the Wagner Group in a bid to further choke off supplies to the contractor.
The Wagner Group, staffed by veterans of the Russian armed forces, has fought in Libya, Syria, the Central African Republic and Mali, among other countries.
"It is apparent that Wagner is emerging as a rival power center to the Russian military and other Russian ministries," the official said.