New satellite imagery indicates that Iran has covered all tunnel entrances at its Isfahan nuclear facility with soil, a move that analysts say reflects deep concern in Tehran over the possibility of an American or Israeli military attack.

In a new report released this week, the Washington-based Institute for Science and International Security stated that images captured on Sunday show two of the tunnel openings fully buried. The third entrance, located on the northern side of the complex, appears to have been reinforced with what the group described as “additional passive defense measures.”

According to the institute, vehicles are no longer visible near the entrances, a change that suggests Iran may be bracing for potential airstrikes or even a ground operation by US or Israeli forces targeting the site.

“Backfilling the tunnel entrances would help dampen any potential airstrike and also make ground access in a special forces raid to seize or destroy any highly enriched uranium that may be housed inside difficult,” the institute said, suggesting that Tehran may have relocated sensitive nuclear material into the tunnels for protection.

“Preparations like these were last observed in the days before Operation Midnight Hammer struck facilities at Fordow, Natanz, and Esfahan,” the institute added, using a different spelling for the Isfahan site and referencing US strikes carried out against those facilities last June.

“It appears clear that the Iranians are seriously concerned about a US/Israeli aerial attack and/or raid against this particularly hardened nuclear facility,” the US-based institute said.

Before Israel launched a 12-day war against Iran in June, the Islamic Republic operated three primary nuclear facilities tied to its atomic program. The Isfahan site, located outside the city of the same name, was primarily known for producing uranium gas used in centrifuges for enrichment.

During the conflict last year, Israel struck Isfahan at the outset, and US forces later carried out additional attacks using bunker-buster munitions and Tomahawk cruise missiles. The White House’s National Security Strategy, published in November, said the US operation “significantly degraded Iran’s nuclear program,” though detailed assessments of the damage have not been made public.

Since those strikes, Iran has barred inspectors from the International Atomic Energy Agency from revisiting the targeted facilities.

Satellite photographs obtained last month showed new roofing structures at the Isfahan site. The Institute for Science and International Security assessed that the construction appeared aimed at enabling Iran to “recover any sort of remaining assets or rubble without letting us know what they are getting out of there.”

President Donald Trump has repeatedly pressed Iran to enter negotiations over its nuclear activities, warning that failure to do so could trigger American military action. His initial threats were also linked to Iran’s violent suppression of domestic protests, during which thousands were reportedly killed.

The United States has called on Iran to surrender its stockpile of uranium enriched to as much as 60 percent purity — a level that, according to last year’s estimate by the UN nuclear watchdog, totals more than 440 kilograms (970 pounds) and is only a short technical step from the 90 percent enrichment considered weapons-grade.

Iran continues to deny that it is pursuing nuclear weapons. At the same time, it has enriched uranium beyond levels needed for civilian purposes, limited access for international inspectors, and expanded its ballistic missile program. Prior to the 12-day war in June, Israeli officials asserted that Iran had recently advanced toward weaponization.

During negotiations held in Oman last week, US and Iranian representatives agreed to focus discussions on Tehran’s nuclear program. However, Washington and Israel have also sought to broaden the agenda to include Iran’s ballistic missile development and its backing of regional proxy terror groups, a proposal Tehran has rejected.

{Matzav.com}