A Japanese daily says the U.S. believes that North Korea has started circulating counterfeit U.S. dollars again.

The Sankei Shimbun on Monday cited a report to the U.S. Congress by the Congressional Research Service (CRS) which said that Pyongyang earns twenty-five million dollars a year by circulating abroad so-called "super notes" worth forty-five million dollars.

The Japanese daily said the CRS report was based on information from U.S. intelligence authorities and the Treasury Department, as well as South Korea and Japan.

North Korea is said to be spending its counterfeiting earnings on acquiring technology to make weapons of mass destruction and to fund overseas trips by North Korean government officials.