The New Yorker magazine says the US military has installed bricks that spy in some buildings in Tehran and scattered spying stones along rural roadways.
The eye-popping allegations appear in the latest article about the US response to Iran’s nuclear program by investigative reporter Seymour Hersh, one of a series of articles he has written in The New Yorker over the past several years.
Most of the article in the June 6 issue rehashes analyses and speculation reported over the years in the Iran Times and other publications.
The new assertions are confined to a few paragraphs in the middle of the article in which Hersh describes what he says are operations carried out over 
Hersh implies, but does not directly state, that the US troops have been physically located inside Iran. He says the American soldiers, “working with Iranian intelligence assets, put in place cutting edge surveillance techniques.” That could mean the Iranian hires did the work inside Iran rather than the US soldiers, but Hersh does not make that clear. In earlier articles in past years he said US troops had gone inside Iran.
Hersh says, “Street signs were surreptitiously removed in heavily populated areas of Tehran—say, near a university suspected of conducing nuclear enrichment—and replaced with similar-looking signs implanted with radiation sensors.
“American operatives, working undercover, also removed bricks from a building or two in central Tehran that they thought housed nuclear enrichment activities and replaced them with bricks embedded with radiation-monitoring devices.”
Hersh continues with this James Bond-style description. “High-powered sensors disguised as stones were spread randomly along roadways in a mountainous area where a suspected weapon site was under construction. The stones were capable of transmitting electronic data on the weight of the vehicles going in an out of the site; a truck going in light and coming out heavy could be hauling dirt—crucial evidence of excavation work.”
Hersh also speaks of “constant” satellite surveillance of suspect sites in Iran, but doesn’t conclude that satellite photos would identify construction areas much better than stone transmitters and would provide much more information about the construction site as well.
The general theme of the article is that US intelligence has not found any hard evidence of any of any Iranian program to build a nuclear weapon. That is, however, what the US intelligence agencies have been saying for the past four years.