As Iran hailed “massive progress” toward a deal on its nuclear program, an Israeli official described the terms of the looming agreement as “incomprehensibly” bad and rejected the Obama administration’s contention that it would keep the regime a year away from accumulating enough fissile material for a bomb.

Estimating that a framework deal would indeed be signed soon, and that a full agreement would follow in June, the official lamented the US-led negotiators’ apparent readiness to remove sanctions without Iran being required to halt its global terrorist activities, and listed a host of areas in which Tehran was working against American, Israeli and moderate Arab interests without being made to pay a price.

His comments underlined immense Israeli opposition to the emerging deal that saw Prime Minister Benjamin Netanyahu lobby against it in Congress earlier this month to the abiding anger of the Obama Administration. Charged with forming a new government on Wednesday after winning the March 17 elections, Netanyahu vowed to patch up ties with the US, but insisted Israel would do everything to thwart the emerging Iranian nuclear deal, which he said was “an agreement that endangers us, our neighbors and the world.”

Speaking to the Times of Israel, the Israeli official, who insisted on anonymity, protested that “Iran will retain core capabilities,” under the emerging accord. While the Obama Administration “claims that the Iranians will remain a year away from enough fissile material for a bomb,” he added, “we don’t agree with this determination. It will be less time.”

The official stressed, however, that Israel’s opposition and dismay related to the entire nature of the international negotiation and engagement with the regime in Tehran. “The more important question is, why allow them to be in this situation at all (with core nuclear capabilities intact)?” he asked. “The Iranians are not being required to reveal their secret military projects, their missile stocks are not being discussed, and nor is the terrorism they initiate.”

“Has anyone wondered why the Iranians need centrifuges at all?” the official demanded. “Or why they are not being ordered to stop their support for Islamic Jihad in Gaza and Hezbollah in Lebanon?”

“So yes,” he added, “for Israel, this is a bad deal.. The deal is bad because of its readiness to remove sanctions without any American demand from Iran to stop the terror. I estimate that we will have a framework deal soon, and after that a full agreement in June. This is incomprehensible.”

The official noted that “Iran is working today against American-Arab-Israeli interests without paying a price… They are in control in Baghdad, Beirut, Sana’a and Damascus. They toppled a pro-American ruler in Yemen, and are engaged in battles against Sunnis in Tikrit.”

Despite all this, the Israeli official protested, “the White House sees them as a solution and not as a problem. The administration’s weakness is broadcast across the entire region.

“Look at (the Obama Administration’s) new policy toward Syria. They let Bashar Assad survive, aren’t calling for him to step down, and are pursuing a policy of ‘If you can’t beat them, join them.’ You look at all this and reach the conclusion that a regional deal is being made here. That is, to say to the Iranians, ‘Come fight with us against the Islamic State, and in return we will not touch Assad or Iranian terror.”

As Iranian and American officials held further talks in Lausanne on Friday, a senior Iranian official told Reuters, “There has been massive progress on all the issues.” He added: “There are still disputes over two issues — R&D (research and development) and UN sanctions.”

Iran’s Foreign Minister Mohammad Javad Zarif, for his part, said “The talks are very difficult and very complicated.”

Zarif spoke shortly after his first meeting of the day with US Secretary of State John Kerry.

Zarif also sought Friday to dismiss concerns that his country’s preoccupation with the crisis in Yemen could pre-empt attempts to find common ground at nuclear talks with six world powers, saying the negotiations remained focused on sealing a deal.

Yemen is “the hot issue of the day” and has come up at the talks but “it doesn’t mean that we negotiated about it,” Zarif told reporters.

Saudi-led air strikes on Shiite rebels in Yemen are straining relations between the Sunni Gulf kingdom and predominantly Shiite Iran. Zarif said they “have to stop and everybody has to encourage dialogue and national reconciliation.”

Despite Iran’s concerns over Yemen, however, “our negotiations are confined to the nuclear” issue, he said.

The sides are hoping to narrow gaps in time to reach a preliminary deal by the end of the month. That would allow them to try and negotiate a comprehensive agreement by late June to put long-term curbs on Tehran’s nuclear activities in exchange for sanctions relief.

Iranian officials have been upbeat recently about the chances of making enough progress by Tuesday to permit them to proceed into the summer. But Zarif was less bullish Friday, saying only that he hoped the sides would come to a common understanding by next week.

The Obama administration has made an accord that lessens fear about Iran’s nuclear weapons potential a top foreign policy objective.

Reflecting Tehran’s interest in reaching a deal, Iranian President Hassan Rouhani sent a letter to President Barack Obama and the leaders of the other countries at the talks — Russia, China, Britain, France and Germany. His office said Friday the letters contained proposals on how to reach a deal, without elaborating. Rouhani also spoke to the leaders of Russia, France and Britain by phone.

The fate of a fortified underground bunker previously used for uranium enrichment appeared close to resolution. Officials have told The Associated Press that the U.S. may allow Iran to run hundreds of centrifuges at the formerly secret facility in exchange for limits on centrifuge work and research and development at other sites.

The trade-off would allow Iran to run several hundred of the devices at its Fordo facility, although the Iranians would not be allowed to do work that could lead to an atomic bomb and the site would be subject to international inspections.

In return, Iran would be required to scale back the number of centrifuges it runs at its Natanz facility and accept other restrictions on nuclear-related work.

Instead of uranium, which can be enriched to be the fissile core of a nuclear weapon, any centrifuges permitted at Fordo would be fed elements such as zinc, xenon or germanium for separating out isotopes used in medicine, industry or science, the officials said.

Associated Press contributed to this report.