A top Israeli minister on Tuesday brushed aside President Barack Obama’s pledges to stand by Israel and ensure it is not weakened, saying such promises will be worthless if Iran is allowed to get the bomb.

Obama said Sunday that he would consider it a “fundamental failure” of his presidency if Israel emerges weakened as a consequence of the nuclear agreement with Iran, and promised to “stand by” Israel if it is attacked by any state actor.

Obama’s statements of support “are pleasant-sounding,” Israel’s Strategic Affairs Minister Yuval Steinitz retorted in an interview with Israel’s Channel 2 TV. But, he continued, “no assistance and no backing will help if Iran acquires nuclear weapons.”

Iran openly seeks the annihilation of Israel. A senior Iranian military chief declared, even as the talks on a framework deal continued last week, that Israel’s destruction is nonnegotiable.

Steinitz, a confidant and Likud party colleague of Prime Minister Benjamin Netanyahu, on Monday presented a list of Israeli demandsaimed at improving the terms of the world powers’ deal with Iran in the weeks ahead of its scheduled completion by June 30.

The changes proposed by Steinitz include the following: barring further Iranian R&D on advanced centrifuges; significantly reducing the number of centrifuges Iran would have available to reactivate if it violates the deal; shuttering the Fordo underground enrichment facility; requiring Iran’s compliance in detailing previous nuclear activities with possible military dimensions; shipping its stockpile of lower-enriched uranium out of the country; and ensuring “anywhere, anytime” inspections of Iran’s facilities. Such changes, said Steinitz, would render a final deal “more reasonable.”

Hours later, however, Obama adviser Ben Rhodes ruled out significant changes that would make the deal more stringent for Iran. The deal as it now stands meets the US’s “core objectives,” Rhodes said in Israeli TV interviews. “We believe that this is the best deal that can emerge from these negotiations.”

Netanyahu has been a caustic and relentless critic of the framework deal announced last Thursday, and his personal ties with Obama have been strained by his public opposition to the US negotiating strategy for months.

In a Sunday interview with The New York Times, Obama said he would be willing “to make the kinds of commitments that would give everybody in the neighborhood, including Iran, a clarity that if Israel were to be attacked by any state, that we would stand by them. And that, I think, should be … sufficient to take advantage of this once-in-a-lifetime opportunity to see whether or not we can at least take the nuclear issue off the table.”

He also said that accusations that his administration is not doing all it can to ensure Israel’s security have made recent months a “hard period” for him personally. “It has been personally difficult for me to hear… expressions that somehow… this administration has not done everything it could to look out for Israel’s interest — and the suggestion that when we have very serious policy differences, that that’s not in the context of a deep and abiding friendship and concern and understanding of the threats that the Jewish people have faced historically and continue to face.”

Netanyahu has insisted that he respects the president, and said in US TV interviews on Sunday that the disagreement between them was not personal. “I trust the president is doing what he thinks is good for the United States. But I think we can have a legitimate difference of opinion on this,” Netanyahu told CNN.

The prime minister gave three US TV interviews on Sunday in which he savaged the framework agreement with Iran as paving the way to an Iranian nuclear arsenal.

The Times of Israel has learned that Netanyahu intends to continue his push for “a better deal” in further US media appearances, since he regards American public opinion as the most potential important area in pressing for terms that would thwart Iran’s nuclear drive. Notably, Netanyahu has not invested similar efforts in reaching out to the media of other P5+1 countries.

Israeli officials are also expected to engage in extensive dialogue with their American counterparts, in order to argue for changes in the deal, in the weeks leading up to June 30.

While Rhodes claimed in his Israeli TV interviews on Monday night that “Iran will never be permitted to build a nuclear weapon,” Obama acknowledged in an NPR interview on Monday that, as restrictions in the deal expire, it would leave Iran with a near-zero breakout time to the bomb after 13 years.

Israel is concerned that the deal both legitimizes Iran’s ongoing nuclear drive, and that Iran will outwit the international community, and could potentially break out to the bomb at short notice.