WASHINGTON: An erratic North Korea, with its nuclear weapons and increasingly belligerent tone, poses a serious threat to the United States and East Asia nations, the director of National Intelligence warned Tuesday in the annual accounting of the threats worldwide.

In his extensive overview, James R. Clapper told Congress that a less decentralized terrorist network has significantly altered the threats while the Arab Spring uprising in the Middle East and North Africa has created spikes in the dangers facing American interests in the regions.

The intelligence chief offered a sober assessment of threats from potential cyber attacks, weapons of mass destruction and the months-long civil war in Syria. North Korea, Iran and Syria stirred the most concern as the Obama administration and Congress weigh the effectiveness of sanctions against Pyongyang and Tehran.

Clapper testified just days after North Korea's communist regime said it was scuttling the 1953 armistice that ended the Korean War and has maintained peace on the peninsula for more than half a century. The administration slapped sanctions against North Korea's primary exchange bank and several senior government officials.

North Korea, led by its young leader Kim Jong Un, has defied the international community in the last three months, testing a long-range missile and a third nuclear bomb.

"These programs demonstrate North Korea's commitment to develop long-range missile technology that could pose a direct threat to the United States, and its efforts to produce and market ballistic missiles raise broader regional and global security concerns," Clapper told the Senate Intelligence committee.

While the intelligence community has figured that Pyongyang's nuclear efforts are designed for deterrence, worldwide prestige and coercive diplomacy, Clapper conceded that that the United States does not know what would be the trigger that would prompt North Korea to act to preserve Kim's regime.

Pressed during the hearing, Clapper said he was "very concerned" about Kim 's actions, which have included tough talk as well as a recent invitation to former basketball star Dennis Rodman.

"The rhetoric, while it is propaganda-laced, is also an indicator of their attitude and perhaps their intent," Clapper said. "So for my part, I am very concerned about what they might do. And they are certainly, if they chose ... could initiate a provocative action

against the South."

Testifying before the Senate Armed Services Committee, the general in charge of U.S. Strategic Command said he is "satisfied" that existing U.S. missile defenses can defend against a limited attack from North Korea.

Air Force Gen. Robert Kehler also said he is confident the country is adequately defended from a limited attack by Iran, "although we are not in the most optimum posture to do that today."

The Intelligence panel hearing also sought, in part, to rebuild some trust between the nation's top intelligence officials and senators who complain they have been refused administration documents and other information that are necessary for congressional oversight.

Joining Clapper at the witness table were newly minted CIA Director John Brennan, FBI Director Robert Mueller, Defense Intelligence Agency Director Lt. Gen. Michael Flynn, National Counterterrorism Center Director Matthew Olsen and Assistant Secretary of State for Intelligence and Research Philip Goldberg.

The intelligence chief said that in Syria, President Bashar Assad's inability to quash the uprising increases the possibility that he will use chemical weapons against his people.

"We assess that an increasingly beleaguered regime, having found its escalation of violence through conventional means inadequate, might be prepared to use chemical weapons against the Syrian people," he said. "In addition, groups or individuals in Syria could gain access to chemical weapons-related material."

The United Nations estimates more than 70,000 people have been killed in the civil war, which started two years ago against Assad's rule. Clapper said Assad's days are number, but added that he did not know "how many days."

The intelligence chief said Iran has become so entrenched in Syria that it likely will have some sort of foothold in a post-Assad government.

In assessing Iran, the report stated flatly that Tehran is developing nuclear capabilities to enhance its security and influence and "give it the ability to develop a nuclear weapon." But the report stopped short of saying a decision has been made.

"We do not know if Iran will eventually decide to build nuclear weapons," the report said.

Clapper explained that in the last year, Iran has made progress in working toward producing weapons-grade uranium. However, the report said Iran "could not divert safeguarded material and produce a weapon-worth of weapons-grade uranium before this activity is discovered."