The National Security Agency’s (NSA) Cyber Command has started to hack into ISIS, or ISIL, networks, The New York Times is reporting, citing people with knowledge of its activities. According to the Times, the hacking is focused on several functions, including disrupting the Islamic State’s daily functions, preventing commanders from paying their fighters, and stopping the militant group from spreading its message.

“We are dropping cyberbombs,” Robert Work, Deputy Secretary of Defense, was quoted as saying. “We have never done that before.”

ISIS is arguably one of the most sophisticated militant groups in the world, using a wide array of digital technologies to not only run its operation but also attract new recruits. The militant group’s activities has caught the ire of hacking collective Anonymous. Last year, Anonymous declared a cyber war on ISIS and continues to attack the militant group.

“Expect massive cyber attacks,” an Anonymous member said in a YouTube video in November. “War is declared. Get prepared. Anonymous from all over the world will hunt you down. You should know that we will find you and we will not let you go.”

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Since then, Anonymous members claimed to have exposed or taken down countless accounts allegedly tied to ISIS. The hacking collective has also exposed some e-mail addresses and other information. All the while, ISIS has called Anonymous “idiots,” arguing that its activities would do nothing to stop its activities.

ISIS has an unknown number of accounts on a wide range of social networks designed to recruit new members and spread its propaganda. The militant group is also believed to use encrypted messaging applications to communicate and plot attacks.

Realizing the digital threat ISIS poses to the U.S. and other countries abroad, Democratic Presidential nominee Hillary Clinton said in December that Silicon Valley must play a role, alongside government, to fight the militants.

“It’s time for an urgent dialogue between the government—and not just our government—and the high-tech community to confront this problem together,” Clinton said during a speech at the Brookings Institution. She added that ISIS is growing in numbers and becoming more sophisticated, and will require the combined efforts of “governments and high-tech experts to figure how we disrupt them.”

That said, Silicon Valley argues that it has been doing quite a bit to disrupt ISIS. Both Twitter (TWTR) and Facebook (FB) have both said they’ve removed accounts allegedly tied to ISIS and would continue to do so.

“We share the government’s goal of keeping terrorist content off our site,” Facebook spokesman Andrew Souvall told Fortune in December. “Facebook has zero tolerance for terrorists, terror propaganda, or the praising of terror activity, and we work aggressively to remove it as soon as we become aware of it. If we become aware of a threat of imminent harm or a planned terror attack, our terms permit us to provide that information to law enforcement and we do.”

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According to the Times, however, the government is now stepping in. According the Times’ sources, Cyber Command has been actively targeting other countries, including North Korea and Russia, but has only recently turned to ISIS.

The Times’ sources, who include both “senior and midlevel” government officials, say that the cyber campaign against ISIS started with hacking into the group’s networks to see how it operates. Now, Cyber Command is mimicking commanders’ activities and fooling militants into believing they need to go to a specific location, where the U.S. can more easily attack them with drones or special operations forces. The hacks are also redirecting ISIS cash to other sources, the Times says.

It’s unclear, though, how effective the attacks have proven so far, and the U.S. isn’t saying how well its activities are disrupting ISIS efforts.

But if nothing else, it appears the cyber war with ISIS is on.

The Department of Defense did not immediately respond to a request for comment on the Times’ report.