The threat assessment describes an environment where jihadist terrorists are increasingly decentralized, creating challenges for the prevention of attacks.
Al Qaeda vs. jihadist groups
Many of these groups have gained a foothold in the Arab Spring countries, where a spike in threats to U.S. interests has been recorded, the threat assessment report said.
"The dispersed and decentralized nature of the terrorist networks (that are) active in the region highlights that the threat to U.S. and Western interests overseas is more likely to be unpredictable," it states.
It cites the Benghazi, Libya, attack that killed four Americans, and an attack on an Algerian oil field as examples of how splinter groups or individuals with jihadist sympathies can act, even without direction from higher in the terrorist chain, Clapper told the committee.
'Cyberespionage and cyberattacks'
For the first time, the emphasis of Clapper's report was on cyberthreats, in the form of cyberattacks or cyberespionage.
Already, foreign intelligence and security services have "penetrated numerous computer networks" in the United States belonging to the government and private sector alike, the report says.
Although classified networks have been targeted, the majority of these attacks have involved unclassified networks, it states.
The United States has enjoyed a technological edge over other nations, but advances in information technology and business practices are evening the playing field, according to the report.
"This is almost certainly allowing our adversaries to close the technological gap between our respective militaries, slowly neutralizing one of our key advantages in the international arena," it said.
However, there is only a "remote chance" of a major cyberattack on the United State that would cause widespread disruptions, such as regional power outages, the report says. Most countries or groups don't have the capacity to pull it off.
The report names China and Russia as two of the most "advanced cyber actors," but says they are unlikely to launch an attack.