U.S. intelligence agencies believe Iranian leaders are involved in a divisive debate over whether to develop atomic weapons in light of international sanctions, a U.S. official confirmed to Fox News Wednesday.

An article by The Wall Street Journal revealed that it is likely Tehran is again moving forward with nuclear weapons research, as well as furthering its uranium enrichment. The paper reported that the new national intelligence estimate, or NIE, updated a disputed 2007 report that said Iran’s “arms program had all but halted in 2003,” the paper said.

When asked about the new intelligence estimate at the White House, national security spokesman Tommy Vietor said he would not comment on intelligence matters, but said that the Obama’s administration’s approach with Iran “has been guided by the fact that Iran has failed to demonstrate clearly peaceful nuclear intentions. Iran has engaged in a constant pattern of deception on its nuclear program.”

“Iran has pursued its nuclear program in ways that only deepen the world's concerns, including by building a secret enrichment plant, enriching uranium to higher levels, and refusing to meet its international obligations under the NPT, the UN Security Council and the IAEA,” Vietor said.

The new NIE arrives Mideast unrest spread to Iran, with opposition supporters protesting in Tehran.

Discussing the broad outlines of the findings, National Intelligence Director James Clapper told the Senate Intelligence Committee that Iran remained a challenge and a potential threat despite the internal debate.

"We see a disturbing confluence of events: an Iran that is increasingly rigid, autocratic, dependent on coercion to maintain control and defiant toward the West, and an Iran that continues to advance its uranium enrichment capabilities along with what appears to be the scientific, technical and industrial capacity to produce nuclear weapons if its leaders choose to do so," Clapper told Congress.

The NIE did not, however, “conclude that Iran has relaunched a full-blown program to try to build bombs,” The Wall Street Journal reported.

"We continue to assess Iran is keeping the option open to develop nuclear weapons in part by developing various nuclear capabilities that better position it to produce such weapons should it choose to do so," he said. "We do not know, however, if Iran will eventually decide to build nuclear weapons."

In December, the top U.S. military officer said he believes Iran is trying to build a nuclear bomb, which he said poses a threat to its neighbors, and the United States is "very ready" to counter Iran should it make a move.

"From my perspective I see Iran continuing on this path to develop nuclear weapons, and I believe that that development and achieving that goal would be very destabilizing to the region," Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, said then.

Iran denies it is seeking a nuclear weapon, and denies U.S. claims that it sponsors terrorists. Iran has wary relations with many of its neighbors, who are trading partners with the oil producer but distrust the theocratic government.

The U.S. fears that if Iran masters the technical challenge of building a bomb it could set off a nuclear arms race around the Persian Gulf area.

Mullen said in December that he supports the current strategy of applying economic and political sanctions on Iran to try to dissuade it from building a bomb, while engaging Iran in international negotiations over the scope of its nuclear program. Iran insists it is seeking nuclear energy.

Mullen repeated his view that a pre-emptive military strike on Iran's known nuclear facilities is a bad option that would set off "unintended consequences," but one the United States reserves the right to use. The Obama administration has said it will not allow Iran to become a nuclear weapons state but has never said exactly what it would do to prevent that.

Last April U.S. officials said Iran is pursuing an aggressive missile program, including intercontinental missiles it would need outside expertise to perfect.

Once Iran decided to build one bomb, it could amass enough highly enriched uranium to do so in as little as 12 months, Gen. James Cartwright, the vice chairman of the Joint Chiefs of Staff, said in April. He added that Tehran still would need additional time to test the weapon and make it usable against an enemy.

New nuclear nations generally need three to five additional years to make a usable weapon, Cartwright said, but the time line could be shortened if Iran should pursue a warhead and a missile or other delivery system at the same time.

Opinions vary on how much damage a U.S. or Israeli military strike could do to Iran's nuclear program, which is intentionally opaque and spread among multiple facilities.

U.S. officials generally say that a strike on one or more known facilities would set the program back a few years but not stop it.

The United States also has acknowledged that once a nation has sufficient nuclear scientific and technological prowess, it could rebound from nearly any assault on the facilities used for bomb development.

Fox News’ Mike Emanuel and the Associated Press contributed to this report.

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