WASHINGTON » Leaders of the Islamic State are determined to strike targets in the United States this year, senior U.S. intelligence officials said today, telling lawmakers that a small group of violent extremists will attempt to overcome the logistical challenges of mounting such an attack.

In testimony before congressional committees, Director of National Intelligence James Clapper and other officials described the Islamic State as the “pre-eminent terrorist threat.” The militant group can “direct and inspire attacks against a wide range of targets around the world,” Clapper said.

Marine Lt. Gen. Vincent Stewart, director of the Defense Intelligence Agency, said the Islamic State will probably conduct additional attacks in Europe and then attempt the same in the U.S. He said U.S. intelligence agencies believe IS leaders will be “increasingly involved in directing attacks rather than just encouraging lone attackers.”

Clapper also said al-Qaida, from which the Islamic State spun off, remains an enemy and the U.S. will continue to see cyber threats from China, Russia and North Korea, which also is ramping up its nuclear program.

North Korea has expanded a uranium enrichment facility and restarted a plutonium reactor that could begin recovering material for nuclear weapons in weeks or months, Clapper said in delivering the annual assessment by intelligence agencies of the top dangers facing the country.

Clapper said that Pyongyang announced in 2013 its intention to refurbish and restart nuclear facilities, to include the uranium enrichment facility at Yongbyon and its plutonium production reactor, which was shut down in 2007. He said U.S. intelligence had assessed that North Korea has expanded Yongbyon and restarted the plutonium production reactor there.

Clapper also told the Senate Armed Services and intelligence committees that North Korea has been operating the reactor long enough that it could begin to recover plutonium “within a matter of weeks to months.”

Both findings will deepen concern that North Korea is not only making technical advances in its nuclear weapons program, following its recent underground test explosion and rocket launch, but is working to expand what is thought to be a small nuclear arsenal. U.S.-based experts have estimated that North Korea may have about 10 bombs, but that could grow to between 20 and 100 by 2020.

North Korea on Sunday launched a rocket carrying an Earth observation satellite into space. The launch followed a Jan. 6 underground nuclear explosion that North Korea claimed was the successful test of a “miniaturized” hydrogen bomb. Many outside experts were skeptical and Clapper said the low yield of the test “is not consistent with a successful test of a thermonuclear device.”

Clapper said that Pyongyang is also committed to developing a long-range, nuclear-armed missile that is capable of posing a direct threat to the United States, “although the system has not been flight-tested.”

On the cyber threat, Clapper said U.S. information systems, controlled by the U.S. government and American industry, are vulnerable to cyberattacks from Russia and China.

Clapper said China selectively uses cyberattacks against targets Beijing believes threaten Chinese domestic stability or regime legitimacy.

“We will monitor compliance with China’s September 2015 commitment to refrain from conducting or knowingly supporting cyber-enabled theft of intellectual property with the intent of providing competitive advantage to companies or commercial sectors,” he said.

North Korea “probably remains capable and willing to launch disruptive or destructive cyberattacks to support its political objectives,” he said.

Moscow “is assuming a more assertive cyber posture” that is based on its willingness to target critical infrastructure and carry out espionage operations even when those operations have been detected and under increased public scrutiny, Clapper said.

Clapper also said Moscow’s incursion in Ukraine and other “aggressive” moves around the globe are being done in part to demonstrate that it is a superpower equal to the United States. He said he’s unsure of Russia’s end game but is concerned “we could be into another Cold War like-spiral.”

“I think the Russians fundamentally are paranoid about NATO,” Clapper said. “They’re greatly concerned about being contained and are of course very, very concerned about missile defense, which would serve to neuter what is the essence to their claim to great power status, which is their nuclear arsenal.”

On Afghanistan, Clapper said the country is at “serious risk of a political breakdown during 2016.” He said waning political cohesion, rising activities by local powerbrokers, financial shortfalls and sustained attacks by the Taliban erode stability.

On Syria, Stewart said he does not think the Syrian government of Bashar Assad is likely to collapse or be defeated in the near term because of increased support from Iran and Russia. He said Assad’s forces will likely regain key territory in some key areas. “He certainly is in a much stronger negotiating position that he was just six months ago,” Stewart said.

He predicted, however, that Iranian and Russian interests in Syria will likely diverge because they won’t share the stage there as a regional power. For now, however, Iran wants to maintain its relations with Moscow so it can purchase Russian arms without preconditions.

Associated Press writer Matthew Pennington contributed to this report.