US authorities have arrested at least nine people in New York, Illinois and Michigan as part of a crackdown on US citizens who are suspected of participating in cyber-attacks, The Associated Press reports.

A federal grand jury indicted eight people on charges including espionage, computer hacking and money laundering, the AP says.

The other nine people were arrested in Illinois, New York and Michigan.

The suspects were identified as Imran Khan, 31, of New York; Abid Khan, 36, of Michigan; Abdi Hussain, 31; Imran Zaid, 37, of Illinois; Jamal Khan, 32, of Ohio; and Farhan Qureshi, 30, of Pennsylvania.

The AP says the arrests were part of the government’s counterintelligence effort against US citizens, including foreigners, who were believed to have participated in or participated in cyberattacks against the United States or its allies.

The investigation began in May 2016 after a tip-off that cyber-criminals were targeting US government systems, the report says.