Iran’s supreme leader has reacted to an open letter from Republican senators in the US by saying that Tehran will take no lessons from Washington.

Ayatollah Ali Khamenei added that he was concerned about the fate of nuclear talks because the other side was “deceitful and back-stabbing”.

Last week, 47 senators wrote an unprecedented letter to “the leaders of the Islamic Republic of Iran”, in which they said a nuclear agreement could be reversed with “the stroke of a pen” after Barack Obama leaves office. The letter has caused controversy in the US.



The letter by American senators indicates the collapse of political ethics in the United States Ayatollah Khamenei

“The letter by American senators indicates the collapse of political ethics in the United States,” Khamenei said on Thursday during a meeting with members of Iran’s top clerical body, which includes President Hassan Rouhani.

“Governments are bound to their commitments by international laws and would not violate their obligations with a change of government,” he said. “They [the Republican senators] said they want to teach us their own laws but we don’t need their lessons, our officials know how to make agreements binding if there’s a deal.”

Khamenei, who has the final say in all state matters, made clear that Iran’s nuclear negotiators, led by its foreign minister, Mohammad Javad Zarif, have his full support. His backing will shield Iranian diplomats from attacks by hardliners at home as they approach a deadline for a framework deal in the coming weeks.

“The negotiating team that President [Rouhani] has chosen for the talks are good, trustworthy and act based on the interests of the country,” Khamenei said. “But I’m worried because the other side is cunning, deceitful and back-stabbing.

“Each time we approach the deadline for talks, the other side, especially Americans, adopt a harsher and more aggressive tone. This is one of their tricks and a deception.”

Khamenei was speaking to members of Iran’s experts council, which is responsible for appointing and dismissing the supreme leader. But the 75-year-old ayatollah has become so powerful that the council’s supervisory role has diminished to a symbolic one despite members still being elected in public votes. The council appointed the hardline cleric Mohammad Yazdi as its chairman on Wednesday.

In his speech, Khamenei also condemned the Israeli prime minister Binyamin Netanyahu’s recent speech to the US Congress which has polarised opinions both in the US and Israel.

“A Zionist clown went there and made a speech, American officials tried to distance themselves from it by making some remarks but at the same time they accused Iran of terrorism. This claim is ridiculous and despicable.”

Khamenei accused the US and its allies of creating Daesh (the Arabic for Islamic State) and similar terrorist groups in the Middle East. “America supports the bogus Zionist regime which is a terrorising state and that’s the ugliest form of supporting terrorism,” he said.