A day after Iran's supreme leader branded Israel as "the rabid dog of the region," officials in the United States are condemning the offensive remarks.

"Well, obviously we disagree with it profoundly," U.S. Secretary of State John Kerry was quoted as saying by CNN. "It's inflammatory and it's unnecessary, and I think at this moment, when we are trying to negotiate and figure out what can and can't be achieved, the last thing we need are names back and forth."

Kerry made the comments as he addressed the Senate Foreign Relations Committee on Thursday.

U.S. Ambassador to the United Nations Samantha Power, meanwhile, called Ayatollah Ali Khamenei's remarks "abhorrent."

“We obviously condemn the comments of the ayatollah, which are abhorrent,” she told CNN. “We have decades of mistrust, partly on the basis of comments like this, partly on the basis of continued steady progress toward a nuclear weapon. And that’s why we’re in these negotiations in the first place.”

Khamenei told senior military officials in Tehran on Wednesday that Israeli officials "cannot be even called humans," and that Israel was “doomed to extinction."

The statement came as negotiators from Iran the P5+1 – the United States, France, Britain, China, Russia and Germany – convened in Geneva for talks over the Islamic Republic's nuclear program.

Prime Minister Benjamin Netanyahu, who flew to Russia on Wednesday to lobby for tougher terms in the negotiations, said Khamenei's remarks showed Iran had not changed since relative moderate Hassan Rohani was elected as president in June.

"He called Jews 'rabid dogs' and said that they were not human. The public responded to him with calls of 'Death to America! Death to Israel!' Doesn't this sound familiar to you? This is the real Iran! We are not confused," he said.

Foreign Minister Avigdor Lieberman compared the Iranian leader's rhetoric to that used by Nazi Germany.

"Whoever talks about the Jews using the terminology of Goebbels and Hitler certainly has no intention to develop a nuclear program for peaceful purposes," he said.