The United States is "not blind, and I don't think we're stupid" in nuclear talks with Iran, Secretary of State John Kerry said in a US television interview that aired on Sunday.
The top US diplomat also insisted there is "zero gap" between the Obama administration and its commitment to Israel, with diplomatic relations between the two allies under strain over the Iran nuclear talks.
Kerry made his remarks in an interview with NBC's "Meet the Press" program after talks with world powers in Geneva failed to produce a deal to curb Iran's nuclear activities in exchange for sanctions relief
"Some of the most serious and capable, expert people in our government, who have spent a lifetime dealing both with Iran as well as with nuclear weapon and nuclear armament and proliferation, are engaged in our negotiation," Kerry said, speaking after intensive talks.
"We are not blind, and I don't think we're stupid," he said.
"I think we have a pretty strong sense of how to measure whether or not we are acting in the interests of our country and of the globe, and particularly of our allies like Israel and Gulf states and others in the region."
Three grueling days of Iran's parallel talks with the United States, China, Russia, Britain, France and Germany, known as the P5+1, ended with no agreement but the two sides will meet again on November 20.
Hopes had soared for a deal after top world diplomats rushed to Geneva to join the talks, but faded after cracks began to show among world powers when France raised concerns.
Kerry told "Meet the Press" that the United States is "absolutely determined that this would be a good deal or there'll be no deal."
That is why "we didn't close the deal here in the last couple of days, because we are together unified, pushing for things that we believe provide the guarantees that Israel and the rest of the world demand here," he said.
"We're talking about stopping their program where it is, with enough guarantees to know that it is in fact stopped where it is, while we then negotiate the full measure of the deal with our allies, with our friends, with all of the interested parties, advising at the table, consulting, and their interests well represented," the US secretary of state said.
Meanwhile hawkish Republican Senator Lindsey Graham, a leading voice in the US Congress on defense and military matters, warned against easing sanctions on the regime in Iran, saying Sunday it could have dire consequences.
"My fear is that we're going to wind up creating a North Korea-type situation in the Mideast, where we negotiate with Iran and one day you wake up, they don't give up their enrichment capabilities, they don't divest themselves of plutonium-producing reactors, centrifuges continue to spin and you're going to have a nuclear Iran," Graham said during an interview on CNN's "State of the Union" program.
French Foreign Minister Laurent Fabius was the first to reveal that a deal had failed, pre-empting the official announcement after the talks broke up.
Fabius had earlier raised concerns that the proposal did not go far enough to curb Iran's nuclear ambitions.
He insisted that France wanted an agreement, despite claims from some officials that Paris had stymied efforts to reach a deal.
The draft deal said to be on the table could have seen Iran freeze parts of its nuclear program in exchange for the easing of some of the sanctions on its battered economy.
He also spoke during the interview on the strength of US-Israeli ties.
"There is zero gap between this president, between this administration and our commitment to Israel, our commitment to its safety, the commitment of the president to our allies in the Gulf and the region," Kerry said.
He added that President Barack Obama "is prepared to engage in an agreement with respect to defending our allies in that region" and "will defend them, as we have in the past, against any kind of external attack."
Meanwhile Israel on Sunday launched a diplomatic offensive to prevent what it considers a "bad and dangerous" deal with Iran.
Prime Minister Benjamin Netanyahu said he spoke to the US, Russian, French, German and British leaders -- five of the six world powers negotiating with Iran -- and "told them that according to the information reaching Israel, the looming agreement is bad and dangerous."
According to Netanyahu, the deal on the table would have removed sanctions on Iran while still enabling the Islamic republic to enrich uranium and
advance works on a plutonium reactor.
"I asked them what was the rush? I suggested they wait, and seriously consider things," Netanyahu said at the opening of Israel's weekly cabinet meeting.
Israeli Economy Minister Naftali Bennett said earlier he would lobby the US Congress to thwart the deal.