The US has accused Israel of spying on international negotiations over Iran’s nuclear programme and using the intelligence gathered to persuade Congress to undermine the talks, according to a report on Tuesday.

The Wall Street Journal cited senior administration officials as saying the Israeli espionage operation began soon after the US opened up a secret channel of communications with Tehran in 2012, aimed at resolving the decade-long standoff over Iran’s nuclear aspirations.

The apparent decision by the White House to leak the allegations is the latest symptom of the growing gulf between Barack Obama’s administration and Binyamin Netanyahu’s government over the Iran talks, in which the Israeli leader suspects US officials of being ready to make too many concessions at the expense of Israeli security. Intelligence analysts suggested that the leak reflects the degree of anger in Washington at Netanyahu’s actions, and could mark a more serious blow to the already tottering relationship.

The leak has come exactly a week before a deadline for the US-Iranian negotiations in Lausanne to produce a framework agreement.

According to the report, the US has long been aware that Israel is among the shortlist of countries with the most aggressive intelligence operations targeting America, alongside Russia, China and France. It said American diplomats attending the talks in Austria and Switzerland were briefed by US counterintelligence officials about the threat of Israeli eavesdropping. It also raised the possibility that Israel gathered intelligence about the US position by spying on other participants in the negotiations, from western Europe, Russia, China or Iran. US intelligence had previously provided help to the Israelis to spy on the Iranians, the report said.

The US also conducts intelligence operations against Israel, and learned of the Israeli spying operation when it intercepted communication between Israeli officials exchanging classified information that US intelligence believed could only have been acquired by espionage.

However, what appears to have upset administration officials more than the spying is the use of the classified intelligence acquired to brief members of the US Congress and to persuade them to torpedo the talks. After Netanyahu addressed Congress this month, 47 Republican senators wrote an open letter to the Iranian leadership, warning it that a successor to Obama could refuse to honour any agreement reached.

“It is one thing for the US and Israel to spy on each other. It is another thing for Israel to steal US secrets and play them back to US legislators to undermine US diplomacy,” the Wall Street Journal quoted a senior US official as saying.

Israel has categorically denied the allegations that it spied on closed-door nuclear negotiations between Iran and the US, however it did not deny that such information had been obtained.

“I think the report is wrong, it is inaccurate,” the outgoing Israeli foreign minister, Avigdor Lieberman, told the country’s Army Radio on Tuesday morning. “The State of Israel obviously has various security interests and we have excellent intelligence services, but we are not engaged in espionage against the United States.” He did not, however, deny information was obtained. Lieberman said: “All the information we gathered was from another entity, not the US.” He added: “We reached a decision a long time ago not to spy on the US and I haven’t come across anyone who has violated that instruction in several decades.”

Ronen Bergman, an expert on the country’s intelligence agencies at the Yedioth Ahronoth newspaper, said: “Whatever you think of Netanyahu’s position on the Iran talks, if he thinks that Israel’s national security is at stake, he has the right to order the intelligence community to find out what is happening.”

But Bergman – whose book, A History of the Israeli Mossad, will be published next year – added: “What worries me and what should be of high concern to the leaders of Israel is that this is ample proof that the relations at large between the US and Israel are sustaining an earthquake. The fact that it is happening is less worrying than that it was leaked. Also, any intervention by Israel in the inner working of American politics is wrong. If this report is true and Netanyahu’s intervention used intelligence material, then it is just making it worse.”

Yuval Steinitz, the strategic affairs minister and close Netanyahu aide, told Israel’s Channel 2 that the reports were “intended to damage the strong ties between the US and Israel, despite our differences on the Iran issue”.

The Speaker of the House of Representatives, John Boehner, said he was “baffled” by the report and denied having received any information from Israel.

“I read that story this morning, and frankly, I was a bit shocked, because there’s no information revealed to me whatsoever,” Boehner, a Republican from Ohio, told reporters at a press briefing. “I was shocked by the fact that there were reports in this press article that information was being passed on from the Israelis to members of Congress. I’m not aware of that at all. I’m baffled by it.”

Other lawmakers also pleaded ignorance when asked about the allegations, which marked the latest front in the escalating row between Netanyahu and Barack Obama. Members of both parties insisted they are regularly briefed on the Iran negotiations by the administration – and no one else.

“No one from Israel’s ever briefed me about the agreement,” the South Carolina senator Lindsey Graham, a Republican, told reporters. “If they’re spying, they’re not telling me about it.”