Islamic State's ideology is "increasingly resonating" with Americans and the trend of the terror group recruiting adherents online is on the rise, according to the US' National Security Agency.
Admiral Mike Rogers, director of the National Security Agency, said on Monday that ISIS' recent efforts to use cyber capabilities as a weapons system rather than only for recruiting and spreading ideology is a "great concern" to the National Security Agency (NSA).
The head of US Cyber Command said that the ability of ISIS to recruit adherents online is "a trend that is clearly increasing, not decreasing" and that the terror group's ideology is "increasingly resonating" with Americans.
Islamic State has seized territory across northern and western Iraq and eastern Syria.
ISIS chief Abu Bakr al-Baghdadi has been incapacitated due to suspected spinal damage and the terror group's shura council is to elect a stand-in leader this week to handle day-to-day affairs, according to media reports.
When it comes to responding to cyber breaches by terror groups as opposed to countries, such as North Korea and China, Rogers said that "every scenario is different."
"I don't have an easy answer. The mechanisms of what you use to apply that pressure, I think, varies by the entity you're trying to shape and let them know, 'hey, you don't want to go down this road, and when you do, you need to know there is a price you're going to pay'," Rogers was quoted as saying by CNN.
The challenge for the NSA, Rogers told a cyber security forum, is the balance between privacy and security.
It is a compromise Congress and the intelligence community must agree on by the end of the month, when the legislation that provides authority to the Foreign Intelligence Surveillance Court expires, he said.
"We have got to create a framework for this programme that enables it to generate its capabilities and insights to defend the nation, but we've got to do it in a way that ensures the privacy of our citizens and engenders greater confidence in our nation about what (the NSA) is doing," he added.