Top intelligence official: ISIS to attempt U.S. attacks this year
On North Korea, Clapper expressed concern about the January nuclear test and Saturday's satellite launch, saying that the country was "committed to developing a long-range nuclear-armed missile that's capable of posing a direct threat to the United States."
Speaking on the nuclear deal with Iran, Clapper said there was no evidence that Tehran was violating the terms of the agreement but said "we in the intelligence community are very much in the distrust-and-verify mode."
The assessment warns that Iran may seek to use detained American citizens as "bargaining pieces to achieve financial or political concessions."
With regards to Russia, Clapper said that "despite its economic challenges, Russia continues its aggressive military modernization," noting that Russian President Vladimir Putin was "the first leader since Stalin to expand Russia's territory."
Clapper also raised cybersecurity as a major concern, saying, "China continues cyberespionage against the United States," and warning that non-state actors like ISIS are developing a cyber capability.
Stewart added that cyberattacks by state actors such as Russia and China target U.S. defense personnel, networks, supply chains and critical structural information.