Two Russian nationals are being prosecuted for allegedly crypto mining on Russian government-owned computer systems, state news agency TASS reported Monday.

“In Russia, there have been two cases recently when people were brought to criminal responsibility for getting access to computers [of state organizations] and using them to mine cryptocurrencies,” TASS quotes Nikolay Murashov, deputy director of the National Coordination Center for Computer Incidents, as saying during a press conference.

According to the TASS report, one of the nationals is a resident of Kurgan who used almost a whole botnet in various regions of the country. A criminal case was initiated against a second national for using the site of JSC Rostovvodokanal for mining. The report gives few other details but quotes Murashov as saying the attackers “infected” web pages and mined crypto currency at the moment the pages were viewed in the browser.

Murashov said companies must be on the lookout for suspicious activity on their networks, even if no activity is immediately detected.

“Up to 80 percent of the computer’s free power can be used to generate virtual coins, and a legitimate user may not even know about it,” he said.

Unsanctioned crypto mining schemes have flourished in Russia. County governments have found operations lurking on their servers, as have airports and oil transport companies.

In October, three nuclear scientists were convicted and penalized for illegally mining bitcoin in the Sarov lab, where the former Soviet Union developed its first nuclear bombs.

The government claims crypto mining is widespread. In 2017 a top technology advisor to President Vladimir Putin estimated that 20 percent to 30 percent of devices “are infected with” crypto mining viruses.