Washington diplomats and American nuclear experts suspect Iran's illicit quest for a nuclear weapon, still suffering from a cyberattack of unknown origins last year, has hit a new set of production and engineering troubles.

At Iran's main nuclear facility in Natanz, home to cascading centrifuges required to make the enriched uranium needed for nuclear weapons, output has slowed dramatically, according to two new reports from the Institute for Science and International Security, or ISIS. For the first time, Iran's centrifuges have seen their average output decrease.

(Click here and here for the ISIS reports.)

David Albright, former United Nations weapons inspector at ISIS, said it's a sign that not only was Iran hurt by the computer virus known as Stuxnet, but that aggressive United Nations sanctions to block the flow of vital weapons-making material into Iran are starting to have a real impact.

"Iran probably cannot build more than a certain number of these first-generation centrifuges. There's some parts in them that require high-tech steel and a particular form, and it looks like Iran cannot get any more," Albright told Fox News. "The major result is that the output at the Natanz enrichment site is actually decreasing."

Albright said the original IR-1 centrifuges are getting old and outdated, and Iran needs 1,000 more of them to produce the same amount of low-enriched uranium from a year earlier. The Stuxnet malware, which targeted the Natanz centrifuges, appears to be causing residual breakage, and the original centrifuges are difficult to manufacture or replace.

Add the poor nuclear performance report to a list of misfortunes for Iran this month. First, one of its top admirals announced Iran would deploy a fleet of naval vessels across the Atlantic for the first time, making stops in South America and the Gulf of Mexico. It appears that was an empty threat, because so far, no ships have made it past the Suez Canal.

Next, high-ranking Iranian officials were implicated in a botched terror plot to kill the Saudi ambassador to the United States in Washington, D.C. State Department spokesman Mark Toner said that failed attack is just another sign that the Iranian regime is under pressure.

“You have seen public statements that are confusing," Toner said. “Iran's president denied the plot but the foreign minister made an offer to investigate.”

In an interview with Al Jazeera television, Iranian President Mahmoud Ahmadinejad said the U.S. was trying to divert attention from its own economic woes.

"I think that there are some people in the U.S. who want this [a war] to happen, but I think there are wise people in the U.S. administration who know they shouldn't do such a thing."

Publicly, White House and Pentagon officials say a military response to Iran's actions will never be ruled out, but privately, officials in Washington say it's very unlikely this most recent provocation gives cause for an attack.

Nevertheless, in a somewhat rare show of force, the U.S. military currently has two aircraft carriers in the region off the coast of Iran, the USS George H.W. Bush in the Persian Gulf and the USS John C. Stennis in the Gulf of Oman.