US Secretary of State John Kerry said Friday that any future Israeli military action against Iran over its nuclear program would be a “huge mistake.”

Asked on NBC’s TODAY show if the nuclear deal signed between the world powers and Iran last week in Vienna would make it more likely that Israel would attempt an attack, Kerry said: “That’d be an enormous mistake, a huge mistake with grave consequences for Israel and for the region, and I don’t think it’s necessary.”

He added: “Iran would then have a reason to say, ‘Well, this is why we need the bomb.'”

Kerry is on a fervent campaign to promote the nuclear accord, which has been met with opposition, mainly from Israel and Saudi Arabia and other Gulf states.

He was speaking about the deal on Friday at the Council on Foreign Relations in New York City and was then set to meet with leaders from the American Jewish Committee and the Conference of Presidents of Major American Jewish Organizations. Some Jewish groups, including the Conference of Presidents and the Anti-Defamation League, have vehemently opposed the deal with Iran, which has pledged to destroy Israel.

In his NBC interview Friday, Kerry said the agreement was the best the White House could get with a country it doesn’t trust.

“There is no trust — no no no. This is not based on trust,” he said on the TODAY show. “That’s what’s important to understand. Everything in this agreement is verifiable. It is a process by which we will know what they’re doing.”

“There is a lot of politics going on. The more people learn about this agreement, the more people are learning this is the only viable alternative to be able to control Iran’s already existing nuclear program. People forget, when President [Barack] Obama came into office and when I became secretary of state, Iran already had in the tens of thousands of centrifuges. They already had fissile material, enough for 10 to 12 bombs. What we’ve done is roll that program back and provide a capacity to have inspectors going forward so we will know what Iran is doing,” Kerry said.

Taking on the argument by opponents of the deal that a better agreement could have been reached — one that would not leave it a nuclear threshold state, as Prime Minister Benjamin Netanyahu has argued — the secretary of state said, “the alternative is to have no inspectors, not know what Iran is doing, go back to where they are today with the ability to make the bomb.”

“And then you’re going to hear everybody say, ‘Uh oh, we’ve got to go bomb them now,'” he warned.

“This is nuclear material. It radiates…This is not something that you can flush down the toilet. It’s not possible,” he insisted.

Former Mossad chief Efraim Halevy (photo credit: CC BY-SA Eli Itkin/Wikimedia Commons)

Former Mossad chief Efraim Halevy (photo credit: CC BY-SA Eli Itkin/Wikimedia Commons)

Kerry also touted the support for the deal of the former head of the Shin Bet Ami Ayalon and the former head of the Mossad Efraim Halevy, who both said this week that when it came to Iran’s nuclear program, this deal was the good option.

“The prime minister doesn’t [like this deal] I understand that. But there are a lot of people in Israel who understand that this is the best way to proceed in order to roll back Iran’s program and make Israel safer,” Kerry said.

Congress has started a 60-day review of the agreement, which lifts economic sanctions against Iran if it curbs its nuclear program’s capacity to build a nuclear weapon.

It is set to vote on the deal by September 17.