Senior Israeli says 'friends don't act like this' after Mossad Head denies US claim that he opposed Iran sanctions in talk with senators.

A senior Israeli official delivered an uncommonly harsh attack on US President Barack Obama's administration Thursday evening, following the American report that alleged that Mossad Head Tamir Pardo had warned US senators against further Iran sanctions, in contradiction of Israel's official stance.

"The fraudulent claims against the Mossad Head were raised by the Americans yesterday, despite a message that had been transmitted to them on Tuesday by Intelligence Minister [Yuval] Steintz,” the senior Israeli source told Channel 2 news.

He added that Israel had gone over the minutes of the meeting between Pardo and the delegation of senators, and that Pardo had not said what was attributed to him.

"Leaking the Mossad Head's statements, even if they had not been falsified, is a serious breach of all the rules,” the senior source added. “Friends do not behave like this. Information from a secret meeting must not leak out.”

Pardo denied on Thursday the report – which was carried by Bloomberg news – claiming that the Mossad disagrees with Prime Minister Binyamin Netanyahu about the need to press new sanctions on Iran.

The report said that Mossad officials advised US senators who were visiting Israel recently to hold off on further Iran sanctions, saying that they would hamper, not help, efforts to persuade Iran to give up or allow full international supervision of its nuclear program.

"The Head of Mossad did not say that he opposes additional sanctions on Iran,” said the spy agency Thursday.

"Mossad Head Tamir Pardo met on January 19, 2015, with a delegation of US senators,” Mossad said in a statement. “The meeting was held at the request of the senators and with the prime minister's approval. At the meeting, the Head of Mossad stressed the extraordinary effectiveness of the sanctions that have been placed on Iran for several years in bringing Iran to the negotiating table.”

"The Head of Mossad noted that in negotiating with Iran, a policy of 'carrots and sticks' must be adopted, and there are not enough 'sticks' nowadays,” it added.

Furthermore, said the agency, he “said specifically that the agreement that is being formed with Iran is bad and could lead to a regional arms race.”

Sources in Jerusalem told Army Radio Thursday that the story reported in Bloomberg about disagreement between Netanyahu and the Mossad regarding sanctions on Iran is US President Barack Obama administration's “revenge” for Netanyahu's invitation to address Congress.

The invitation was extended by Congress without consulting Obama.