Accusations that Israel planted spying device around Washington, D.C., to spy on President Donald Trump were met with surprise among former intelligence workers, even those used to the cynical world of espionage.
According to the ex-officials, such a targeted operation is a significant violation of norms, even for a state like Israel which has a reputation for pushing the boundaries.
For Israel, they said, extremely aggressive tactics even towards allied nations appears to be the norm in many cases.
First reported by Politico, US agents are said to have found at least three "stingray" devices around Washington, D.C.
Stingrays mimic cell phone towers in an effort to intercept data from devices, gather data and voice calls from individual devices, and are meant for highly-targets intelligence operations.
According to Politico, which cited multiple former intelligence officials, the US concluded that the culprit was Israel.
Israeli officials immediately denied allowing intelligence operations to take place against US targets. The pushback included a firm statement from Prime Minister Benjamin Netanyahu, who faces a pivotal election this week.
Allegations of Israeli spying inside the US became a major issue decades ago with the discovery and arrest of Jonathan Pollard, a one-time analyst for the Office of Naval Intelligence, who was convicted of passing critical Cold War-era secrets to Israel. He was sentenced to 30 years in prison.
The US itself has apologized for spying on world leader's phones and communications in the past, most notably apologizing to German Chancellor Angela Merkel in 2015 for targeting of German officials' phones over a period of years.
Part of the strength of the reaction among former officials comes between the more widely-accepted "passive" monitoring — where states scoop up data indiscriminately in case it is useful later — and "active" monitoring, a more invasive method where agents target particular people.
"That's a huge difference in terms of offense," said a NATO military intelligence official based in Brussels. "It's very hard to get particularly angry at the Americans for scooping up all the world's data and calls because everyone is jealous and would do the same if they had that passive capability."
"Pulling everyone's calls out of the ether and tracking them is certainly an invasion of privacy but arguably its a passive one, in the case of the Germans, they were just as mad it could be done as they were that it was done," the source said.
"The Israelis apparently sent a team to plant devices on US soil to capture data from the apparently insecure mobile phone of the president of the United States? That's what we call an active measure and it's simply not allowed."
Asked about the denials from Israel, the NATO official seemed unconvinced. "I don't know who placed those devices myself but Israel is on a very short list of 'friends' who would do that to an ally," said the official.
Part of the context, according to a former member of the CIA's clandestine service who worked in the Middle East, and asked not to be identified by name, is an institutional, boundary-pushing mentality in the Israel intelligence services.
"When any intelligence service operates abroad with clandestine gathering, there's a clear process based on the relationship between the two countries," the former agent said.
"Operations are often run through the target country's embassy with the ambassador's knowledge and approval. And most services — say US officers working in France on a jihadist thing — are forced to bring in the local service to avoid scandals and mistakes.
"Targeting French citizens in France with a hands-on operation would be strictly forbidden without the involvement of the French services."
But the Israelis see things differently, according to the former CIA officer. "We always knew that, yes, the United States and Israel are friends, even close friends, and cooperate on a range of issues usually related to Iran and terrorism," the official said.
"But when working with and around them, its standard policy to act like you're dealing with a hostile service such as China or Russia."
"If it's perceived to be in the Israeli interest to f— with your operation or hassle your sources or apply tight surveillance, they have a much longer leash than any Western service," they said.
"Israel might be our ally and our intelligence services might cooperate on the highest levels, but, on the street, you pretty much have to assume the Israelis are capable of things no other ally would attempt."
Both sources say they were shocked that the Israelis considered it worth the risk to conducting such an operation against a US president.
"It goes to show how much the Israelis believe certain geopolitical rules don't apply to them when the United States is involved," said the NATO official.
"It seems like they have a strong sense they can ride out any scandal with their strong political support inside the US."
A consultant who works with UK intelligence in London was even more blunt. "[Israeli intel acts] purely act out of self interest as you would expect," said the consultant.
"They are not interested in the bigger picture, only their own interests. They have no morals when it comes to spying on allies."
The consultant has had first-hand experience with such behavior, including a course he taught on contract to the UK Ministry of Defense a few years ago.
The course, the source said, was filled with members of UK, NATO and other aligned services, including Israel.
"The only person expelled from this UK MOD Intelligence training course in the UK was the Israeli invitee," he said. "I was on that course giving a lecture. He had a dodgy briefcase. He was kicked out…"