LONDON — The United States has opened a new line of combat against the Islamic State, directing the military’s six-year-old Cyber Command for the first time to mount computer-network attacks that are now being used alongside more traditional weapons.
The effort reflects President Obama’s desire to bring many of the secret US cyberweapons that had been aimed elsewhere, notably at Iran, into the fight against the Islamic State — which has proved effective in using modern communications and encryption to recruit and carry out operations.
The National Security Agency, which specializes in electronic surveillance, has for years listened intensely to the militants of the Islamic State, and those reports are often part of the president’s daily intelligence briefing.
But the NSA’s military counterpart, Cyber Command, was focused largely on Russia, China, Iran, and North Korea — where cyberattacks on the United States most frequently originate — and had run virtually no operations against what has become the most dangerous terrorist organization in the world.
The goal of the new campaign is to disrupt the ability of the Islamic State to spread its message, attract new adherents, circulate orders from commanders, and carry out day-to-day functions, like paying its fighters.
A benefit of the administration’s exceedingly rare public discussion of the campaign, officials said, is to rattle the Islamic State’s commanders, who have begun to realize that sophisticated hacking efforts are manipulating their data. Potential recruits might also be deterred if they come to worry about the security of their communications with the militant group.
A review of what should be done to confront the Islamic State is on Obama’s agenda Monday, when he is scheduled to attend a conference in Hanover, Germany, with the leaders of Britain, France, Italy, and Germany.
Of these efforts, the cybercampaign is the newest. It is also the one discussed in least detail by officials of many countries, and its successes or failures are the most difficult to assess from the outside.
Defense Secretary Ashton Carter is among those who have publicly discussed the new mission, but only in broad terms, and this month the deputy secretary of defense, Robert O. Work, was more colorful in describing the effort.
“We are dropping cyberbombs,” Work said. “We have never done that before.”
The campaign has been conducted by a small number of “national mission teams,” newly created cyberunits loosely modeled on Special Operations forces.
While officials declined to discuss the details of their operations, interviews with more than a half-dozen senior and midlevel officials indicate that the effort has begun with a series of “implants” in the militants’ networks to learn the online habits of commanders.
Now, the plan is to imitate them or to alter their messages, with the aim of redirecting militants to areas more vulnerable to attack by US drones or local ground forces.
In other cases, officials said, the United States may complement operations to bomb warehouses full of cash by using cyberattacks to interrupt electronic transfers and misdirect payments.
The fact that the administration is beginning to talk of its use of the new weapons is a dramatic change. As recently as four years ago, it would not publicly admit to developing offensive cyberweapons or confirm its role in any attacks on computer networks.