The U.S. National Science Foundation (NSF) has banned a researcher for using supercomputer resources to generate bitcoin.

In the semiannual report to Congress by the NSF Office of Inspector General, the organization said it received reports of a researcher who was using NSF-funded supercomputers at two universities to mine bitcoin.

Mining is a process to generate the digital currency that involves complex calculations. Bitcoin can be converted to traditional currencies, and 1 bitcoin was worth roughly US$654 on Friday, according to indexes on CoinDesk.

The computationally intensive mining took up about $150,000 worth of NSF-supported computer use at the two universities to generate bitcoins worth about $8,000 to $10,000, according to the report. It did not name the researcher or the universities.

The universities told the NSF that the work was unauthorized, reporting that the researcher accessed the computers remotely, even using a mirror site in Europe, possibly to conceal his identity.

The researcher said he was simply conducting tests, Inspector General Allison Lerner's office wrote in the report, which covers six months to March 31.

"The researcher's access to all NSF-funded supercomputer resources was terminated," the office wrote. "In response to our recommendation, NSF suspended the researcher government-wide."

The office, which is tasked with promoting efficiency in NSF programs and detecting cases of fraud, did not release other details of the case.

It did not immediately respond to a request for more information.

The incident follows a similar case in February in which a researcher at Harvard University was caught using supercomputer resources to mine dogecoin, a recently launched virtual currency.

The researcher was barred from accessing the computer resources.