A high-ranking government official has denied a Los Angeles Times report that North Korea has printed counterfeit American bills for more than 25 years.

The official on Tuesday said a North Korean defector quoted by the daily as saying he worked at the North's mint never did so, adding no North Koreans living in South Korea have worked there.

The report said the United States will step up its crackdown on fake bills from North Korea regardless of the impact on the six-way nuclear talks.