JERUSALEM, Nov. 21 (Xinhua) -- An Israeli diplomatic source told Xinhua Thursday that Iran's toughening of stance at its nuclear talks with the P5+1 group was likely to scrap an emerging interim agreement between the two sides.

On the second day of the talks in Geneva, Iran hardened its nuclear stance, compared with in the previous round of negotiations, by saying they would not tolerate a ban on their right to enrich uranium.

Iranian Deputy Foreign Minister Abbas Araqchi said early Thursday that the right to continue enriching uranium is a "red line," while demanding some sanctions on Iran's oil trade and banking system be removed.

"Iran's insistence on enriching uranium speaks volumes," the Israeli source said, arguing the Shi'ite country was showing the world its "real face" despite the efforts made by the United States, France, Britain, China, Russia and Germany in Geneva.

While the West wants Iran to stop its uranium enrichment, U.S. Secretary of State Kerry said Wednesday that the issue would not be decided in the interim agreement.

Meanwhile, some U.S. officials said there was no rush on their part to reach an agreement with Iran.

The Ma'ariv daily quoted a U.S. official as saying: "This has to be a good deal, and the first step needs to advance us towards an overall agreement."

Many Israeli officials fear that the battle on the interim agreement has already been lost, as Israeli Prime Minister Benjamin Netanyahu would return from Russia later Thursday without gaining much support.

After securing France's tough stance toward Iran earlier this week, Netanyahu failed to win over Russian President Vladimir Putin to side with him on the issue on Wednesday.

The Israeli prime minister charges that a nuclear Iran would be a threat to Israel's existence, citing the anti-Semitic and anti- Western comments made by Iranian officials as justification for his argument.

"They should not have nuclear weapons and I am committed to preventing them from possessing it," Netanyahu said in Moscow on Thursday, prior to his return to Israel.