US President Barack Obama with Israeli Prime Minister Benjamin Netanyahu in the Oval Office of the White House in Washington, D.C., in 2013. Reuters In a revelation that is bound to further erode an already tense relationship between the US and Israel, Israel has reportedly been spying on nuclear talks with Iran — and then using the inside info to lobby members of Congress to kill the deal.

Officials told The Wall Street Journal that the spying began last year after the US and other interested parties entered negotiations on slowing down Iran's nuclear program.

This news comes after a tumultuous few weeks following Israeli Prime Minister Benjamin Netanyahu's address to a joint session of Congress. In that address on March 3, Netanyahu passionately declared that the emerging agreement with Iran was a "bad deal."

The Journal report cites "current and former" White House officials who said Israel's spying activity was an attempt to "penetrate the negotiations and then help build a case against the emerging terms of the deal."

This has apparently upset some of the officials who have knowledge on the ongoing negotiations.

From The Journal:

The espionage didn't upset the White House as much as Israel's sharing of inside information with US lawmakers and others to drain support from a high-stakes deal intended to limit Iran's nuclear program, current and former officials said.

US President Barack Obama said there was "nothing new" about Israel's position regarding talks with Iran. He told the Associated Press: "Netanyahu's alternative to the talks amounts to no deal at all."

Still, the latest wrinkle in the matter has not done well to get the US and Israel closer to a consensus. The Journal cites one senior US official who laid a out a clear point on Israel's tactics: "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.”

Israel denied it was spying on the talks.

Israeli officials were reportedly upset that they were left out of the loop. A former US official told The Journal that Israeli officials said: "'Did the administration really believe we wouldn’t find out?'"