The US defence department has reportedly raised its assessment of the espionage threat posed by Israel to the highest category of “critical”, according to media reports citing American intelligence and defence officials.

The assessment, first published by NBC News on Friday and followed by The New York Times, comes at a time when Washington is pursuing diplomatic engagement with Iran, while its ally Israel is opposed to the talks aimed at ending the conflict now 100 days long on Sunday.

US President Donald Trump and Israeli Prime Minister Benjamin Netanyahu have publicly diverged in their approach to the war – Washington wants to extricate itself amid political pressure, while Israel is still pushing to topple the Iranian government.

This is not the first time Israel has been accused of espionage against the US – its closest ally and benefactor – with which it maintains extensive security and intelligence cooperation.

Here is what you need to know:

What did the Pentagon say?

According to NBC News and The New York Times (NYT), citing anonymous current and former US officials, the Pentagon’s Defense Intelligence Agency (DIA) arm recently upgraded Israel’s counterintelligence threat level from “high” to “critical”, the most serious designation in its internal assessment system.

The warning was based on Israeli intelligence agencies intensifying efforts to collect information on US military personnel, government officials and policy discussions.

The news reports said the concern was focused on American officials involved in shaping Washington’s approach towards Iran, as the two foes continue to negotiate an end to the war that has sent global energy prices soaring.

“An intensified Israeli effort to learn about US positions in talks with Iran has crossed a line, according to some American officials,” the NYT said.

According to the news outlet, intelligence assessments pointed to increased Israeli surveillance efforts in recent weeks targeting US military and government figures.

They include Trump envoy and key negotiator Steve Witkoff; the Pentagon’s top policy official, Elbridge A Colby; and one of his deputies, Michael P DiMino IV, the NYT reported.

Witkoff was chief negotiator in the nuclear talks before Israel and the US launched the attack on Iran on 28 February.

The reports also referenced incidents in which US defence personnel working in Israel allegedly discovered software on their phones “to tap their communications had been surreptitiously installed on their phones”, the NYT added.

The newspaper said the DIA reports found Israeli spying on the US, which has occurred before, surged from late 2024 onwards, coinciding with US President Joe Biden’s administration stepping up pressure on Israel over its genocide in Gaza.

The reported increase in spying continued after Trump was elected to a second term in November 2024 and began shaping his administration’s policy towards Iran.

Tensions between Trump and Netanyahu have come to the surface in the past week, amid reports the US president called the Israeli prime minister “f****ing crazy”, due to Israel’s escalation in Lebanon. At least 3,500 people have been killed in Israeli attacks in Lebanon.

Trump has been pressing Israel to halt its attacks on Lebanon, but the bombardment in the south has continued, undermining a potential deal with Iran which insists both issues are inseparable.

While intelligence gathering between friendly nations is not unusual, some US officials reportedly believe recent Israeli activities have gone beyond what Washington traditionally considers acceptable among allies.

According to officials cited in the reports, US intelligence agencies have become increasingly concerned that Israel is seeking greater insight into US policy discussions and negotiating positions, specifically with Iran.

What has been the response from the Israeli and US governments?

Israel has denied the allegations.

According to NBC, the Israeli embassy in Washington said it was “completely false” that the country spies on US government officials or American institutions.

“Israel does not gather intelligence on American entities, let alone US government officials,” NBC quoted the spokesperson as saying.

A White House official also reportedly dismissed the NBC report, saying the “entire story is false and sourced to someone who doesn’t have any knowledge of what’s going on”.

Al Jazeera could not independently verify the media reports and the US and Israeli responses.

Has Israel previously spied on the US?

Yes. Israel has previously been involved in espionage cases targeting the US, although such incidents have not been spoken about much given their close ties.

The most famous example is the Jonathan Pollard affair. The civilian intelligence analyst working for the US Navy was arrested in 1985 after passing large quantities of classified information to Israel. He later pleaded guilty to espionage and served 30 years in prison before being released on parole in 2015.

The Pollard case remains one of the most significant espionage scandals in the history of US-Israeli relations and continues to shape perceptions within parts of the American intelligence community.

However, espionage between close allies is not uncommon, says academic Andreas Kreig.

“Israel has a particularly long track record of conducting intelligence operations inside the United States,” the professor at the Department of Security at King’s College London told Al Jazeera.

“Over decades, Israel has sought to penetrate US policymaking circles through both formal and informal networks, including intelligence and lobbying channels, in order to gain insight into American strategic thinking and decision-making,” he added.

Nevertheless, Washington has for years provided billions in military aid and weapons sales to Israel, including throughout the ongoing Israeli genocide in Gaza.

The US Congress is also currently debating a section of a new defence bill, which would integrate the two countries’ research and development for weaponry to an unprecedented degree. The US has also provided diplomatic cover to Israel at the UN and other international bodies.

Why has Israel allegedly ramped up its espionage activities in the US?

According to academic Kreig, Israel is “deeply concerned” about the trajectory of US negotiations with Iran.

“From the Israeli perspective, the recent conflict with Iran was effectively a joint US-Israeli war, yet the United States is now in a position to shape the diplomatic endgame,” he told Al Jazeera.

“The principal Israeli concern is that Washington could agree to a deal that establishes an enduring diplomatic framework, potentially lasting years or even decades, which would constrain Israeli freedom of military manoeuvre against Iran in the future. Israeli policymakers therefore have a strong incentive to stay ahead of US deliberations and understand negotiations in real time.”

Moreover, Kreig said Israeli intelligence gathering also serves a “strategic purpose”, which is to identify “opportunities to influence, derail, or undermine negotiations if Israeli leaders judge the process to be contrary to their security interests”.

“While Israel sees the United States as its indispensable patron and closest strategic partner, it has simultaneously treated the US as a legitimate intelligence target whenever interests diverge,” he added.

“What surprises many observers is the extent to which Israel, despite being heavily dependent on American military, diplomatic and financial support, has developed the capacity to penetrate multiple layers of US policymaking and cultivate influence across key institutions involved in American statecraft.”

According to analyst and Iran expert Negar Mortazavi, Israel’s reported espionage in the current context is not new and has past precedent. Israel’s opposition to US-Iran negotiations goes back to the time of US President Barack Obama when he signed a nuclear deal with Iran in 2015, which the US under Trump withdrew from in 2018.

“The Israeli Prime Minister Netanyahu did not want any deals or serious negotiations or normalisation between Tehran and Washington, and he tried to stop it publicly and privately in any way he could,” she told Al Jazeera.

Moreover, Mortazavi said the ongoing war on Iran was “not going as planned or as promised”, and that Trump wants “to exit the war and he has to do it through diplomacy”.

“At this point it is very clear that US interests and Israeli interests are no longer overlapping, they’re divergent,” she added.