The Iran nuclear deal would "codify a perfectly aligned pathway for Iran to get a nuclear weapon, Senate Foreign Relations Chairman Bob Corker told administration officials on Thursday.

Noting "an amazing transition that has occurred," Corker accused Secretary of State John Kerry and other administration officials of giving Iran what it wanted — an industrial-sized nuclear program — after two years of negotiations he said were intended to dismantle that program.

The deal would freeze Iran's nuclear program for 10 years in exchange for relief from international sanctions that have crippled the country's economy and legitimacy for its Shiite Muslim theocracy. The U.N. Security Council approved it on Monday — a move that has angered congressional Republicans who had asked the administration to give Congress the first say.

Turning to Kerry, who took notes as he spoke, Corker said: "What you have really done here is you have turned Iran from being a pariah to Congress — Congress — being a pariah."

"They already have what they want. They got it 10 years ago or more," Kerry responded, repeating his claim that Iran was able to master the nuclear fuel cycle during the previous administration of President George W. Bush. "It isn't a question of giving them what they want. It's about holding their program back."

He strenuously denied that the administration's goal had shifted in the talks, saying it always has been to close off Iran's pathways to a nuclear weapon.

"We set our standard and we believe we have achieved that standard," Kerry said. "Nobody has ever talked about actually dismantling their entire program"

The hearing is one of several scheduled dives into the 159-page deal as lawmakers consider whether to vote to approve or disapprove of it. Under a law passed this year, Congress has 60 days to act, during which President Obama cannot waive any sanctions against Iran enacted into law. That restriction becomes permanent only if lawmakers pass a resolution of disapproval and override Obama's promised veto. Otherwise the deal will take effect as signed.

Most Republicans already have come out against the deal. Corker was one of only a handful of Republican senators who refused to sign an open letter in March to Iran's leaders warning that any deal might not outlast Obama's presidency.

The committee's ranking Democrat, Ben Cardin of Maryland, implored members to keep an open mind about the deal, in spite of deep skepticism that Iran can be trusted to keep it.

"We don't trust Iran. But we've got to leave emotion out of this," he said.