IDF fighter jets covertly flew into Iranian air space in 2012 in what was thought to have been a dry run for a commando raid at a sensitive nuclear site, according to an extensive report published by the Wall Street Journal on Thursday.
The report, based on the testimony of almost two dozen senior US and Israeli officials, reveals the breakdown in relations and open mistrust that led to mutual spying between Israel and the US over Iran's nuclear program.
The highlight of tensions came in 2012, when the US spied on Israel as it sent a jet to apparently hold a trial run for an attack on Fordow, Iran's most fortified nuclear facility that is built into the side of a mountain.
Responding to the flight, the US sent a second aircraft carrier to the Middle East and prepared fighter jets "in case all hell broke loose," according to a senior US official.
Meanwhile the US was hiding its attempts to reach a nuclear deal with Iran secret from Israel, causing a situation in which both sides were forced to start spying on each other.
"After working in concert for nearly a decade to keep Iran from an atomic bomb, the U.S. and Israel split over the best means: diplomacy, covert action or military strikes," wrote the Wall Street Journal, noting that the sides may still be on a "collision course" if Israel feels pressed to strike Iran's nuclear program.
Back in 2009, the report reveals the two sides worked together to come up with options against Israel, which saw the CIA and Mossad plan covert action. However, Mossad leaders said US officials made clear they were not interested in taking more serious actions against the Islamic regime to block its path to a nuclear arsenal, such as by collapsing its financial system or regime.
US officials say the Mossad began to run several covert operations unilaterally given the lack of US cooperation, such as the assassination of Iranian nuclear scientists.
"Going through the porch entrance"
Then, in 2010, the Stuxnet computer virus was used by the US and Israel to thwart Iranian centrifuges. But after the virus spread accidentally on the internet, US President Barack Obama called for more caution, while Israel argued the steps were only slowing, and not stopping, Iran's nuclear program.
"Cyber and other covert operations had their inherent limitations,” one senior Israeli official said, “and we reached those limitations.”
At around that point in time Prime Minister Binyamin Netanyahu began to work to formulate a military strike on Iran's nuclear infrastructure.
The US claimed Israel didn't have the right equipment to take out Iran's facilities, but Israel responded by briefing the US on its attack plan: cargo planes would drop IDF commandos in Iran to "blow the doors, and go in through the porch entrance” of Fordow to sabotage the nuclear facility, according to a senior US official.
In response the US said the plan was too dangerous and demanded advance warning before the attack was launched.
"Whether this was all an effort to try to pressure Obama, or whether Israel was really getting close to a decision, I don’t know,” said Michéle Flournoy, who served as undersecretary of defense for policy at the time.
Dry run
Then in early 2012, US spy agencies picked up a flurry of meetings between Netanyahu and his top security advisers, which Israeli officials say ranged from mission logistics to the fallout caused by the strike.
The US increased satellite surveillance of Israeli aircraft, picking up when IDF pilots were put on alert on moonless nights that would increase the cover for an airstrike. They likewise spied on Israeli practice missions and intelligence gathering to find weak points in Iran's air defenses.
Officials say it appeared Israel conducted a dry run of the attack, although the information was so classified or fragmentary that few knew exactly what was going on.
Tensions heightened amid an Israeli request for V-22 Osprey aircraft that can take off and land like helicopters, making them perfect for dropping commandos. Likewise Israel wanted to obtain the Massive Ordnance Penetrator, a 30,000-pound bunker buster bomb designed to destroy Fordow.
According to Gary Samore, who was Obama's White House coordinator for arms control and weapons of mass destruction for four years, Netanyahu wanted "somebody in the administration to show acquiescence, if not approval” for a military strike.
"The message from the Obama administration was: ‘We think this is a big mistake,'" he revealed, noting that the White House turned down the requests.
Obama's secret talks
For his part, Obama was pressing for a nuclear deal with Iran, the leading state sponsor of terrorism. Back in December 2011, then-Senator John Kerry was sent to discuss diplomatic channels with Iran in a meeting with leaders of Oman.
The White House hid the talks from Israel, deciding only to give Netanyahu information if a deal appeared possible.
The first secret negotiations with Iran were held in July 2012 and fell through, but "nobody was willing to throw it overboard by greenlighting Israeli strikes just when the process was getting started," according to a former senior Obama administration official.
Israeli communications were being spied on by the US to see if the secret talks had been exposed.
During a visit by Netanyahu's then-national security adviser Yaakov Amidror in September 2013, the White House got the answer to that question.
Amidror was told by White House national security adviser Susan Rice that Obama was making an historic call with Iranian President Hassan Rouhani.
In response, Amidror revealed that Israel had identified the tail numbers on the unmarked US government planes flying negotiators to Muscat, Oman, where the secret talks were taking place.
Amidror said it was insulting for Obama's officials to think "they could go to Oman without taking our intelligence capabilities into account," and called the decision to hide the talks from Israel a big mistake.
It remains to be seen how the path will proceed for Israel and the US on the Iran issue now that the controversial Iran deal has been sealed.
The deal sees Western powers obligated to protect Iranian nuclear sites from sabotage, and while State Department officials claimed Israeli strikes would not be included, US Secretary of State John Kerry has indicated the US would defend Iran from Israel.