Iran's recent actions to cut off access of the International Atomic Energy Agency "will greatly reduce our capabilities to detect unreported nuclear material and activities," top nuclear inspectors acknowledged Wednesday in a memo from the nuclear watchdog agency obtained by FOX News.

On Sunday, Iran declared that it is ending "voluntary" cooperation with the IAEA, and on Monday, Tehran ordered the IAEA to remove all agency surveillance equipment and personnel beyond those agreed to in the 1970 Nuclear Non-Proliferation Treaty's "safeguards" agreement.

That move immediately set U.S. government officials to studying the impact of Iran's eviction notice to determine which sites and activities would be left unmonitored.

Wednesday's memo states that "nothing is to be removed" from Natanz, home of Iran's nascent uranium enrichment program. The same was initially thought to be true of Isfahan, the plant where the Iranians are converting uranium ore into hexafluoride gas, a key intermediate step toward the development of nuclear fuel and nuclear weapons. But the memo states that while "everything [is] still in place" there so far, IAEA officials are "assessing" the situation and "expect" that the agency "will still maintain some containment and surveillance measures there as well."

The last line is a clear indication the IAEA expects to lose some of its monitoring capability at Isfahan.

Two senior State Department officials interviewed by FOX News about the memorandum said Wednesday that the likely effect of Iran's eviction notice this past Monday will be minimal in terms of IAEA monitoring of those sites and activities that are already known, but significantly damaging to IAEA efforts to probe new information about previously "unreported" activities and sites.

The officials also largely confirmed a Washington Post article published Wednesday that says U.S. intelligence has helped drive international action against Iran at the IAEA. Officials confirmed specific documents and drawings cited that represent the most incriminating intelligence the United States had obtained through its acquisition of an Iranian laptop computer. The officials also verified when the computer was acquired and when the Iranians learned the United States had it as well as the forensic analysis performed on the laptop by the CIA, and they said that a Pakistani associate of A.Q. Khan, the father of Pakistan's nuclear program, currently being held in a Malaysian prison was interrogated by U.S. officials.

But officials disagreed with the article's assertion that the intelligence "has confounded efforts by policymakers, intelligence officials and U.S. allies to reach a confident judgment about Iran's intentions."

The author "downplays the level of confidence that people have in the evidence," one official said.

"She accentuates the normal caveats that intelligence people put into everything they write," added another official.

"Just like [with] Iraq, all of our allies agree with us" on the authenticity of the laptop intelligence and the American conclusion that Iran is trying, at a minimum, either to build an atomic weapon or to preserve its capability to do so, said the first official.

James Rosen joined Fox News Channel (FNC) in 1999. He currently serves as the chief Washington correspondent and hosts the online show "The Foxhole." His latest book is "A Torch Kept Lit: Great Lives of the Twentieth Century" (Crown Forum, October 4, 2016).