Vice President Joe Biden said on Monday the letter 47 Republican senators sent to Iran's leaders was "beneath the dignity of an institution I revere," CBS News reported.

Led by Arkansas Sen. Tom Cotton, the lawmakers cautioned Tehran that any deal it strikes with the United States on its nuclear program needed congressional approval. Otherwise, it would amount to nothing more than a "mere executive agreement" between President Barack Obama and Iranian Ayatollah Ali Khamenei, according to Fox News.

"The next president could revoke such an executive agreement with the stroke of a pen, and future Congresses could modify the terms of the agreement at any time," the Republicans said.

Biden, who also serves as president of the Senate, fired back in a sharply worded statement, MSNBC noted.

"This letter, in the guise of a constitutional lesson, ignores two centuries of precedent and threatens to undermine the ability of any future American president, whether Democrat or Republican, to negotiate with other nations on behalf of the United States," he wrote. "Honorable people can disagree over policy. But this is no way to make America safer or stronger."

Cotton, for his part, did not hold back either when he responded to Biden's allegations on Tuesday morning.

"Joe Biden, as Barack Obama's own secretary of defense has said, has been wrong about nearly every foreign policy and national security decision in the last 40 years," he said with a nod to former Pentagon chief Bob Gates' memoir.

"If Joe Biden respects the dignity of the institution of the Senate, he should be insisting that the president submit any deal to approval of the Senate, which is exactly what he did on numerous deals during his time in Senate," he added.

The signers of the original Republican letter to Tehran included Republican heavyweights, such as Majority Leader Mitch McConnell of Kentucky and presidential hopefuls Ted Cruz of Texas and Rand Paul of Kentucky. However, seven GOP senators -- Alaska's Lisa Murkowski, Arizona's Jeff Flake, Maine's Susan Collins, Mississippi's Thad Cochran, Ohio's Dan Coats and Tennessee's Lamar Alexander and Bob Corker -- did not adhere to the letter.