Washington’s top negotiator to the six-way nuclear talks says North Korea has clearly counterfeited U.S. dollars.

In a meeting with South Korean journalists in Washington Tuesday, Assistant State Secretary Christopher Hill said he had personally seen the so-called “super notes,” adding that Pyongyang must immediately stop all of its counterfeiting activities.

Hill said he believes the communist state has printed hundreds of millions dollars worth of counterfeit 100-dollar bills.

However, he was quick to add that North Korea’s counterfeiting and other illicit activities should be dealt with separately from the six-way talks on settling the North’s nuclear standoff.