John Kerry, President Joe Biden’s climate envoy, is facing calls from Republicans to resign after audio was leaked of an Iranian official saying Kerry told him about Israeli attacks against Iran’s interests in Syria.

Kerry, who served as secretary of state under former President Barack Obama from 2013 to 2017, has denied the allegations.

Audio surfaced Sunday of Iranian Foreign Minister Mohammad Javad Zarif being interviewed in March by an economist named Saeed Leylaz. Among the revelations from the conversation, Zarif said Kerry told him that Israel attacked Iranian assets in Syria 200 times.

“Kerry has to tell me that Israel has attacked you 200 times in Syria?” said Zarif, who complained that Iran’s military withheld information from him on crucial matters. 

“You did not know?” the interviewer asked.

“No, no,” Zarif replied.

Kerry tweeted Monday evening: “I can tell you that this story and these allegations are unequivocally false. This never happened - either when I was Secretary of State or since.”

Earlier Monday, several Republicans called for Kerry’s resignation.

“I don’t do this lightly,” Sen. Dan Sullivan of Alaska said on the Senate floor. “In my entire time in the Senate, I’ve never called for anyone’s resignation. But his record, John Kerry’s record, of undermining working families and working against American national security interests was too much to bear. He needs to go.”

“It's unfathomable that any U.S. diplomat, past or present, would leak intelligence to the world's leading sponsor of terrorism at the expense of one of our staunchest allies,” Rep. Mike Gallagher of Wisconsin said in a statement. “If this report is accurate and he did leak intelligence, John Kerry should resign."

Sen. Rick Scott of Florida said Biden should revoke Kerry’s access to classified information while an investigation is conducted.

“[T]hese allegations involving John Kerry are deeply disturbing and must be explained immediately,” Scott said in a statement. “Until we have clarity and know the truth, President Biden must remove John Kerry from all access to and briefings on national intelligence. If these allegations are true, he must resign.”

Sen. Lindsey Graham, R-S.C., meanwhile, appeared to defend Kerry.

"I don’t know if we should trust that tape or not,” he said. “If it’s true, it’s very damaging. I like John Kerry, but that would not be helpful, and it would be very problematic if it were true. But let’s wait and see how authentic this is."

Iranian Foreign Ministry spokesman Saeed Khatibzadeh did not dispute the recording’s authenticity Monday but claimed it had been “selectively” edited.

Zarif did not say when Kerry made the alleged comments to him. Kerry and Zarif spoke often while they were negotiating the 2015 Iran nuclear pact.

It’s also not clear if the information would have been classified at the time. 

A 2018 Reuters article, for example, reported that Israeli Intelligence Minister Israel Katz said in a speech that “in the last two years Israel has taken military action more than 200 times within Syria itself,” while citing “preserving the red line, preventing the things that Iran has done” among its goals.

Added State Department press secretary Ned Price on Monday: “I would just make the broad point that if you go back and look at press reporting from the time, this certainly was not secret. And governments that were involved were speaking to this publicly, on the record.”

The controversy surrounding Kerry comes as the Biden administration is trying to rejoin the nuclear deal from which Trump withdrew the U.S. in 2018.

Republicans used the leaked Zarif tape to reiterate their opposition to returning to the pact.

“Above all, this clearly shows why the United States cannot for a second entertain re-entering the failed Iran Nuclear Deal,” Scott said.

In the recording, Zarif also claimed Russia wanted to stop the nuclear deal, and he criticized Islamic Revolutionary Guard Gen. Qassem Soleimani's separate relations with Russia. A U.S. drone strike in 2020 killed Solemani in Baghdad, an attack that at the time brought the U.S. and Iran to the brink of war.

“I have sacrificed diplomacy for the battlefield more than the price that (those on) the battlefield (led by Soleimani) ... paid and sacrificed for diplomacy,” Zarif said.

The Associated Press contributed to this report.