The United States was not involved with the explosion at Iran’s Natanz nuclear site on Sunday, the White House stated on Monday.

“The US was not involved in any manner,” White House Press Secretary Jen Psaki said during a press briefing. “We have nothing to add to the speculation about the causes or the impact.”

Despite the US claim of lack of involvement in the incident, Iran’s foreign minister warned Tuesday that an attack on its main nuclear enrichment site at Natanz affects ongoing negotiations in Vienna over its tattered atomic deal with world powers.

Mohammad Javad Zarif’s remarks were made in Tehran alongside visiting Russian Foreign Minister Sergey Lavrov. While not claiming the attack, Israel is widely believed to have carried out the still-unexplained assault that damaged centrifuges there.

Zarif said that Israel’s sabotage was a “very bad gamble” if it thought that the attack would decrease Iran’s leverage in having sanctions lifted.

“Americans should know that neither sanctions nor sabotage actions would provide them with an instrument for talks,” Zarif said. “They should know that these actions would only make the situation difficult for them.”

Kayhan, the hard-line Tehran newspaper, urged Iran to “walk out of the Vienna talks, suspend all nuclear commitments, retaliate against Israel and identify and dismantle the domestic infiltration network behind the sabotage.”

“Despite evidence that shows the role of the U.S. as main instigator of nuclear sabotage against Iran, unfortunately some statesmen, by purging the U.S. of responsibility, (aid) Washington’s crimes against the people of Iran,” the paper said in Tuesday’s editions.

While Kayhan is a small-circulation newspaper, its editor-in-chief, Hossein Shariatmadari, was appointed by Supreme Leader Ayatollah Ali Khamenei and has been described as an adviser to him in the past.

Such a walkout remains unlikely as the administration of President Hassan Rouhani, whose main diplomatic achievement was the 2015 accord, hopes to get the U.S. to rejoin it and provide desperately needed sanctions relief. However, pressure does appear to be growing within Iran’s theocracy over how to respond to the attack.

In remarks aired late Monday by state television. the former head of the country’s civilian nuclear arm offered his own description of the attack, calling its design “very beautiful.” The attack appeared to target both the power grid at Natanz, as well as the facility’s emergency backup power fed by separate batteries, Fereydoun Abbasi said.

Abbasi said a similar attack targeted Iran’s underground Fordo facility in 2012 with two explosions: one 30 kilometers (18.5 miles) away at a power station and the other at Fordo’s emergency battery system.

“We had predicted that and we were using a separate power grid,” Abbasi said. “They hit but nothing happened for our machines.”

It remains unclear on which power source Natanz in central Iran relies. Satellite photographs appear to show an electrical substation at the facility’s northwest corner.

(YWN Israel Desk – Jerusalem & AP)