Top White House officials have revealed that Israel began to spy on the closed-door nuclear negotiations between Iran and P5+1 last year in order to sink an agreement.

Current and former American officials told the Wall Street Journal that the spying operation was part of a campaign by Israeli Prime Minister Benjamin Netanyahu to “penetrate the negotiations and then help build a case against the emerging terms of the deal.”

The newspaper reported on Monday that Israel was spying on the talks by eavesdropping and getting information from confidential US briefings, informants and diplomatic contacts in Europe.

According to the US officials, Israel shared information from the talks with American lawmakers and others to drain support from a nuclear agreement.

“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,” an unnamed senior American official was quoted as saying by the Wall Street Journal.

American intelligence agencies learned Israel’s espionage operation when they intercepted communications among Israeli officials that carried details from the confidential talks.

However, Israel denied spying on the negotiation team of the Obama administration directly.

Tel Aviv has been persistent to undermine the talks and prevent a nuclear deal between Tehran and the five permanent members of the UN Security Council – the US, Britain, Russia, China, France – plus Germany (P5+1).

Netanyahu travelled to the United States earlier this month and delivered a warning speech to the US Congress to stop a potential agreement.

On Monday, 367 members of the House of Representatives signed a letter, telling President Barack Obama that any nuclear accord must constrain Iran’s nuclear program for “decades” before Congress will roll back sanctions.

“A final comprehensive nuclear agreement must constrain Iran’s nuclear infrastructure,” the letter said.

In any agreement, “Congress must be convinced that its terms foreclose any pathway to a bomb, and only then will Congress be able to consider permanent sanctions relief,” according to the letter.

Netanyahu’s efforts to sabotage the nuclear negotiations have angered President Obama.

Obama said the re-election of Netanyahu would not affect his support for any possible deal with Iran.

“Our goal is to get this done in a matter of weeks, not months,” Obama said in an interview with the Huffington Post.

China has urged all sides involved in the negotiations over Tehran’s nuclear program not to lose any time in the bid for a comprehensive agreement.

Speaking at a regular press conference on Monday, Chinese Foreign Ministry Spokesperson Hong Lei urged all sides in the negotiations about Iran’s nuclear program to build up political will in an attempt to reach a comprehensive agreement.

“The negotiation on a comprehensive agreement on the Iranian nuclear issue has come to a critical point… All parties concerned should build up political will, work towards the shared goal, waste no time in making political decisions and make joint efforts to clinch a final deal through negotiation,” Hong said.

He added that during the latest nuclear talks between Iran, P5+1 and the EU in Lausanne, Switzerland, all participants demonstrated “strong political will, pragmatic attitude for negotiation and innovative thinking.”

The Chinese official pointed out that important progress has been made in Lausanne while the gaps still remain.

He said Beijing pursues an “objective and unbiased” approach to the Iranian nuclear issue and plays a constructive role in advancing the negotiations.

“The Chinese side put forward a host of ‘China solution’ and ‘China thinking’ on relevant focal and thorny problems during the negotiations to bridge differences among all parties and contribute ‘China wisdom’ to the negotiations. We will continue to make relentless efforts together with other parties,” Hong said.

Zarif, Lavrov discuss talks

Meanwhile, foreign ministers of Iran and Russia have exchanged views on the latest developments pertaining to Tehran’s nuclear program and vital issues relating to bilateral cooperation.

In a phone conversation on Monday, Iran’s Foreign Minister Mohammad Javad Zarif and his Russian counterpart Sergey Lavrov discussed the settlement of the nuclear issue ahead of a new round of talks between Iran and P5+1.

A fresh round of nuclear talks is scheduled to resume in the Swiss city of Lausanne on Thursday with a planned visit between Zarif and US Secretary of State John Kerry.

The latest round of nuclear negotiations ended in Lausanne on March 20 after six days of intensive and serious talks with both Iran and the United States citing progress.

The Iranian foreign minister said on Friday that “good progress” had been made over the six days of the latest round of negotiations and pointed out that some work still needed to be done.

The US secretary of state also said, “We’ve made a lot of progress.”

The talks between the United States and Iran are part of broader negotiations between the Islamic Republic and P5+1 — Russia, China, Britain, France and the United States plus Germany — to reach a comprehensive agreement on Tehran’s nuclear program as a deadline slated for July 1 draws closer.