Republicans have accused former Secretary of State John Kerry of mishandling classified material and of treason after Iran's foreign minister Mohammed Javad Zarif revealed he had received from his US counterpart sensitive information about Israeli military operations in Syria.
In an audiotape leaked on April 25, Zarif said Kerry had told him that Israel had attacked Iran’s assets in Syria at least 200 times.
The accusation led to a backlash against Kerry, who now serves as President Joe Biden's special envoy for climate.
“People are talking about treason—and I don’t throw that word around a lot,” Senator Dan Sullivan of Alaska said.
"This is something that deserves a Senate investigation. If it indeed is proven to be accurate, then John Kerry should seriously consider resignation,” Tennessee Senator Marsha Blackburn, a member of the Senate Judiciary Committee, told Fox News.
She added, "This is something that is serious. This is someone who has served our nation at very high levels, that had information, whether as a senator or as secretary of state and knew what was happening on the diplomatic and military front, to give that information to someone who is an adversary is something of tremendous concern to me."
Legislators called on Biden to pressure Kerry to resign over the leaked tape.
Mitt Romney from Utah called on Tuesday for “transparency,” saying this issue has to be evaluated. “We need this kind of transparency associated with this kind of an apparent breach of a commitment to one of our key allies,” he said.
Wisconsin Representative Mike Gallagher told Politico: "It's unfathomable that any US diplomat, past or present, would leak intelligence to the world's leading sponsors of terrorism at the expense of one of our staunchest allies."
Kerry denied in a tweet the allegations that he leaked classified information about Israeli operations in Syria to Iran.
"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," Kerry wrote.