The U.S. military has launched an aggressive cyberwar campaign against the Islamic State in Iraq and Syria (ISIS) that is targeting the terrorist group’s ability to communicate and spread propaganda online, The Associated Press reported Friday.

Anonymous officials told the AP that U.S. Cyber Command, a relatively new division that began operating in 2010, is testing a range of operations intended to disrupt ISIS’s online activities.

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The attacks include efforts to prevent the group from spreading propaganda, recruiting members through social media and conducting financial or logistical transactions, according to these officials.

Defense Secretary Ashton Carter on Thursday told a House Appropriations Committee subcommittee that such operations were underway but declined to give details. Much of the campaign is classified.

The push comes after months of pressure from Carter, who has urged commanders to ramp up the offensive against ISIS in the cyber domain.

Officials say Carter has been frustrated that as Cyber Command has grown, it has focused on the threat from nation states — such as Iran, Russia and China — rather than developing a force to counter the growing insurgent presence online.

"Why should they be able to communicate? Why should they be using the Internet?" Carter said Thursday before the Appropriations subcommittee on defense. "The Internet shouldn't be used for that purpose."

Officials have increasingly been forced to grapple with ISIS’s use of online tools to achieve its goals, including radicalizing lone-wolf attackers on U.S. soil. The December attack in San Bernardino, Calif., that killed 14 stoked fears that the group has become increasingly savvy at using social media to recruit followers.

The group has an extensive presence on Twitter. A March study from the Brookings Institution estimated that from September to December 2014, ISIS supporters used at least 46,000 Twitter accounts, although not all of them were active at the same time.

But experts warn that cracking down on ISIS online could have an unintended consequence: It could stymie needed intelligence-gathering efforts. Terrorist chatter on Twitter, for example, provides officials with a valuable stream of information.

“If every single ISIS supporter disappeared from Twitter tomorrow, it would represent a staggering loss of intelligence,” a March report from the Brookings Institution noted.

Civil liberties advocates say the U.S. must be careful not to affect civilian networks or critical infrastructure that could harm civilians if they were damaged.

They also warn that deactivating large groups of ISIS-associated social media accounts could chill an outlet for free speech in regions where dissidents rely on the Internet to make their voices heard.

The Pentagon is in the process of ramping up its cyber force, building 133 teams by 2018 — 27 of which are designed for combat.

“We recognize that cyber can be a tool that we can use against our enemies,” Carter said Thursday.