Microsoft has emerged as a kind of internet cop, thanks to its efforts to thwart Russian hackers.

The company’s announcement Tuesday that it disrupted fake internet domains mimicking conservative U.S. political institutions sparked confusion and alarm on Capitol Hill. It also led Russian officials to accuse the company of participating in an anti-Russian “witch hunt.”

Microsoft stands virtually alone among tech companies with its aggressive approach, which uses U.S. courts to fight computer fraud and seize hacked websites back from malicious perpetrators. In the process, it takes on a role that might look more like the job of government than a corporation.

The company’s discovery this week was part of an ongoing legal fight against Russian hackers that began in the summer before the 2016 presidential election.