Joe Biden said the US would only lift sanctions on Iran if it stops enriching uranium, and would not remove them simply to attract Tehran back to the negotiating table.

Asked on CBS News if the US would lift sanctions first to encourage Iran back to talks, Mr Biden responded: “No.”

Pressed on whether he would first demand Tehran stop enriching uranium, he nodded.

The US president’s response came as Iran’s supreme leader reiterated Tehran would not return to full compliance with the nuclear accord it signed with world powers in 2015 until the US lifted all sanctions.

“If the US wants to go back to its commitment under JCPOA [the nuclear accord], it should lift sanctions altogether . . . in practice not in words or on paper,” Ayatollah Ali Khamenei said at a meeting with the army’s top brass marking the 42nd anniversary of the Islamic revolution.

“We will then verify the US measures and if we are confident the sanctions are lifted properly, we could go back to our commitments,” adding “we will not return from this policy”.

Commenting on Sunday’s apparent stalemate, an Iranian analyst who asked not to be named, said “If the US retreats, its hegemony would be damaged and if Iran retreats it would lose its image and credibility”. He added “This is not a stand-off but needs a change of the game like a visit by the UN secretary-general to Tehran.”

Saeed Laylaz, an analyst close to the government of Hassan Rouhani, said the Ayatollah spoke from a position of power, thanks to the regime’s survival under the toughest of sanctions. But he said the comments did not mean Tehran had hardened its position ahead of possible talks with the Biden administration.

Donald Trump pulled the US out of the nuclear deal in 2018, prompting Iran to roll back most of its commitments under the terms of the accord. The country began a 20 per cent enrichment of uranium in January, an increase from about 4 per cent, a further breach of the agreement, bringing it closer to being able to produce weapons-grade uranium, which requires 90 per cent purity. Iran denies any intention to make a bomb.

Emmanuel Macron, president of France, last week said he could be an “honest broker” in negotiations between the US and Iran, adding that Saudi Arabia and Israel had to be involved in the next round of talks given their concerns about Tehran’s regional and military policies. Khamenei hit back, implying the French president was not in a position to tell Iran what to do.

Biden’s National Security Advisor Jake Sullivan last Thursday said the US was “actively engaged” in consultations with its European allies to “produce a unified front when it comes to our strategy towards Iran and towards dealing with diplomacy around the nuclear file”.

The Ayatollah said he would not respond to “some nonsense” by figures in Europe and the US. “Logically speaking, the US and three European states trampled upon all their JCPOA commitments and have no right to set conditions now,” he said. “The side which can put conditions on is Iran because Iran implemented all its commitments.”