Ed wrote about the attack on Iran’s Natanz nuclear enrichment site yesterday. The U.S. has claimed to have no role whatsoever in the attack and the Iranians are directly blaming the Mossad. Today the Jerusalem Post has a bit more on the explosion that took out the underground electrical system that powers the centrifuges used to enrich uranium.

Fereydoon Abbasi-Davani, former head of Iran’s Atomic Energy Organization, told Iranian media on Monday that the attack hit an electrical substation located deep underground and managed to damage both the power distribution system and the cable leading to the centrifuges in order to cut power to them.

The Iranian official stressed that such an operation takes years, saying “the design of the enemy was very beautiful.”…

The Jerusalem Post has learned that the attack was carried out through an explosive device that was smuggled into the facility and detonated remotely…

Alireza Zakani, head of Iran’s Parliament Research Center, announced in a television interview on Tuesday that “thousands of centrifuges” had been destroyed, damaging “most of the enrichment facilities.”

The NY Times reported yesterday that Iran is vowing revenge:

Mr. Zarif, in a statement broadcast by Iranian state television, said that Israel wanted “to take revenge because of our progress in the way to lift sanctions.”

“But we will take our revenge on the Zionists,” he continued.

Today, Iran also said it would soon be enriching uranium to 60%, higher than ever before:

Iran’s state-run Press TV quoted Iran’s lead nuclear negotiator, Abbas Araghchi, as saying the country informed the International Atomic Energy Agency of plans to start 60 percent uranium enrichment.

The announcement puts Iran closer to weapons-grade levels of more than 90 percent enrichment and exceeds its current top level of 20 percent.

The move adds another major hurdle to negotiations to revive a 2015 nuclear deal negotiated between Iran and six world powers.

They may be doing that eventually but they won’t be doing it soon, at least not at Natanz. It will likely take several months before they can rebuild their operation there.

Meanwhile, talks with Iran over reviving U.S. involvement in the JCPOA were set to continue later this week. Now it’s not clear if Iran will even show up.

And all of that brings us back to the question of who is responsible for this attack. On one hand, Israel may have done this alone as a move against Iran’s nuclear ambitions and as a way to set back talks with the U.S. Iran never supported the JCPOA and would prefer the U.S. not lift sanctions on Iran. As you can see from the quote above, that seems to be what foreign minister Zarif thinks happened here.

On the other hand, the NY Times suggests it’s also possible this is Israel doing the U.S.’s dirty work. Iran had some leverage in those negotiations thanks to the centrifuges spinning at Natanz. They were an implied threat, i.e. lift sanctions on Iran or else. Now that threat is gone and if the U.S. does come back to the deal it would be on terms less favorable to Iran.