Washington (CNN) Iranian Supreme Leader Ayatollah Khamenei joined top U.S. officials Thursday in blasting a letter 47 GOP senators recently sent on the Iran nuclear talks.

Khamenei dismissed the letter as "part of their ploys and tricks," according to Iran's official state outlet, Press TV. The senators, who are highly critical of the deal being worked out, wrote the Islamic Republic to warn its leaders of Congress's role in approving and implementing any agreement.

Khamenei's comments came the day after Secretary of State John Kerry slammed the letter in a Senate hearing and said his reaction to it had been "utter disbelief." President Barack Obama, Vice President Joe Biden and other senior administration figures have also taken strong exception to the GOP move.

JUST WATCHED Biden, Clinton weigh in on GOP letter to Iran Replay More Videos ... MUST WATCH Biden, Clinton weigh in on GOP letter to Iran 01:53

Khomenei's barbs Thursday didn't stop with the GOP senators, however, as he also lashed out at the world powers -- Britain, France, Germany, Russia and China, as well as the U.S. -- sitting across the negotiating table from Iran.

"Of course, I'm concerned because the other side is into deception, trickery and backstabbing," Khamenei said, according to Press TV.

Read More