The United States remains committed to ensuring that Iran never acquires a nuclear weapon and is prepared to engage in diplomacy with Tehran, the U.S. secretary of state said Monday, while the Iranian supreme leader said his country could boost enrichment to 60% if necessary.

"Diplomacy is the best path to achieve that goal. President [Joe] Biden has said: if Iran comes back into strict compliance with the JCPOA (Joint Comprehensive Plan of Action), the United States is prepared to do the same," said Anthony Blinken.

Blinken addressed the High-Level Segment of the Conference on Disarmament in Geneva, saying virtually the body has a responsibility to create new tools to manage 21st-century threats and protect what the world has built.

"Working with allies and partners, we will also seek to lengthen and strengthen the JCPOA and address other areas of concern, including Iran’s destabilizing regional behavior and ballistic missile development and proliferation," he said.

Also, Iran must comply with its safeguards agreements with the International Atomic Energy Agency (IAEA) and its international obligations.

Iran and the IAEA reached a temporary deal on continued nuclear inspections on Sunday, but access will be reduced, IAEA chief Rafael Grossi said after returning from a visit to Tehran.

Tehran had announced last week that it would curb access for IAEA inspectors, in a bid to pressure the United States into lifting sanctions and returning to the 2015 nuclear agreement between Iran and major powers.

Asked whether he would still be able to check if Iran’s nuclear activities were purely peaceful, Grossi said: "Not as I was before, but in a satisfactory manner."

The compromise deal is set to last three months.

Iran could boost uranium enrichment to 60%: Khamenei

Iran’s supreme leader Ayatollah Ali Khamenei said the country could boost uranium enrichment to 60% if needed, defiantly vowing to "not back down on the nuclear issue."

That would be far above the 3.67% limit Iran had accepted under its 2015 landmark nuclear deal with world powers, but still short of the around 90% required to make an atomic bomb.

Iran has repeatedly denied that it is seeking to build nuclear weapons, a point Khamenei reiterated in the comments that were posted on his official website Monday.

Khamenei said that "we will act to the point that is needed and the country requires" and that "we could bring enrichment to 60%" for nuclear propellants and other purposes.

"The Islamic Republic will not back down on the nuclear issue and will strongly continue down the path of what the country requires for today and tomorrow."

Khamenei stressed that it was the United States that left the deal and emphasized that Iran’s suspended commitments "are still reversible" if Washington returns to its commitments.