U.S. President Barack Obama has offered Prime Minister Benjamin Netanyahu immediate talks to upgrade the Israel Defense Forces’ offensive and defensive capabilities in the wake of the deal on Iran’s nuclear program, a senior U.S. official told Haaretz.

In a phone conversation between the two leaders Tuesday, Netanyahu did not respond to the offer, said the official, who requested anonymity.

He said this was the second time Obama had made a direct offer to Netanyahu on launching such talks. The first time was in an April 2 phone call, a few hours after the announcement of the framework nuclear deal in Lausanne, Switzerland.

But Netanyahu did not accept that offer so as to avoid implying that Israel had come to terms with the nuclear deal. Also, in late May, Netanyahu told reporters that Israel would fight the nuclear accord and not seek any kind of reciprocal deal with Washington.

But now Obama has told Netanyahu he understands why the Israeli leader did not accept the April offer, the official said. With the deal with Iran sealed, Obama believes that Israel and the United States should hold talks on how to preserve Israel’s qualitative military edge given the changes that could occur in the region as a result of the nuclear accord.

On Tuesday, Obama told Netanyahu he would send Defense Secretary Ashton Carter to Israel for talks next week. Carter is expected to repeat Obama’s offer, but it is too early to predict the response by Netanyahu and his defense minister, Moshe Ya’alon.

“We’re still waiting for an Israeli answer. If Israel wants to wait until after the Congressional debate on the nuclear accord that’s fine too,” the U.S. official said.

“We’ll be ready to hold these talks then too, because the day after the agreement goes into effect the sun will still shine and Israel and the U.S. will continue to work together on security matters.”

In an interview Tuesday with The New York Times, Obama said: “I’m prepared to go further than any other administration’s gone before in terms of providing them additional security assurances from the United States."

According to Obama, “The thing I want to emphasize is that people’s concerns here are legitimate. Hezbollah has tens of thousands of missiles that are pointed toward Israel. They are becoming more sophisticated. The interdiction of those weapon flows has not been as successful as it needs to be.”

Netanyahu told the Knesset Wednesday he intended to keep fighting the nuclear accord and believed he could succeed.

“The agreement that was signed in Vienna is not the final word,” he said. “We will continue to point out its flaws and dangers, and the danger of making such a deal with a murderous dictatorship.” One way Netanyahu plans to fight the agreement is by trying to persuade the U.S. Congress to vote against the lifting of the economic sanctions on Iran.

Obama said Tuesday he would veto any decision by Congress that could block the implementation of the nuclear accord. A two-thirds’ majority is needed to override a presidential veto, so Netanyahu would have to persuade many Democrats to oppose their president.

In the interview with The New York Times, Obama said he was confident he could get the accord approved by Congress.

“But after that’s done, if that’s what [Netanyahu] thinks is appropriate, then I will sit down, as we have consistently throughout my administration, and then ask some very practical questions: How do we prevent Hezbollah from acquiring more sophisticated weapons?” he said.

“How do we build on the success of Iron Dome, which the United States worked with Israel to develop and has saved Israeli lives?”

Meanwhile, British Foreign Secretary Philip Hammond, who will meet with Netanyahu in Jerusalem on Thursday, said the Netanyahu government would have opposed any agreement.

“Israel wants a permanent state of standoff and I don’t believe that’s in the interests of the region,” he said Wednesday, adding that he would try to explain Britain’s position to Netanyahu — not that he expected to convince him.

“He has made clear that he intends to fight it all the way and that Israel will seek to use its influence in the U.S. Congress to obstruct the progress of the deal,” Hammond said. “I am confident that action will not succeed.”

Hammond expressed the hope that Israel would ultimately adopt a pragmatic approach. Once it had exhausted its efforts to stop the accord, it might “seek to engage in a sensible and pragmatic way to deal with the new reality on the ground in the Middle East, to the benefit of everyone.”

Hammond’s criticism echoed that of his German counterpart, Frank-Walter Steinmeier. “This is a responsible deal and Israel should also take a closer look at it and not criticize the agreement in a very coarse way,” Steinmeier said Tuesday.