Russia’s foreign minister said Tuesday that Iran was willing to halt its 20-percent enrichment of uranium, which has been a key concession sought in international negotiations over Iran’s nuclear program.

That is the highest level of enrichment acknowledged by Iran and one that experts say could be turned into warhead grade in a matter of months.

In an interview with the Kuwaiti news agency KUNA that was released by the Foreign Ministry on Tuesday, Sergey Lavrov said that “for the first time in many years” there are encouraging signs in international efforts to resolve the Iranian nuclear dispute.

He said Iran has confirmed that it is ready to halt production of uranium enriched to 20 percent. He did not give details, but said the sextet of international negotiators should make “substantial reciprocal steps.”

In the interview, Lavrov did not say which Iranian officials had expressed the willingness to pull back on enrichment and when the position was made known. The interview was released a day after Iran’s president-elect Hasan Rowhani promised a “path of moderation” that includes greater openness on Tehran’s nuclear program and overtures to Washington.

But Rowhani also said Iran would not halt uranium enrichment. That could indicate Iran would be satisfied to continue the relatively low-level enrichment needed for fuel rods in the reactor at its atomic energy plant in Bushehr.

Over the past year, the international community has imposed heavy economic sanctions on Iran, hoping they would be so painful that the Islamic Republic’s clerical regime would slow its nuclear program.

“The international community should respond appropriately to the constructive moves by the Iranian side, including step-by-step halting and cancellation of sanctions — unilateral ones and those enacted by the UN Security Council,” Lavrov said.

Any halt in 20-percent enrichment would be a significant concession by Iran, but it would not necessarily mean any drawdown in enrichment capabilities; the labs could concentrate on lower-grade fuel. The 20-percent enriched material is used in Iran’s research reactor and is many steps closer to warhead-grade uranium than the type used in energy reactors.

On Monday, the head of the International Atomic Energy Agency told Reuters that sanctions against Iran were having no effect on slowing down its nuclear program. Yukiya Amano added that the IAEA was still interested in entering talks with Iran about opening up its nuclear sites to inspection.

US President Barack Obama said later that day that the US would be willing to enter talks with Iran over lifting sanctions in exchange for proof that Tehran was not building a nuclear weapon.

“As long as there’s an understanding about the basis of the conversation, then I think there’s no reason why we shouldn’t proceed,” Obama told PBS’s Charlie Rose.

The statement came as part of what some see as a possible opening for a thaw in US-Iranian relations in the wake of Rowhani’s election.

While admitting that policy was still run by the country’s clerical regime, Obama said the election could mark a turning point in relations.

“I do think that there’s a possibility that they decide — the Iranians decide — to take us up on our offer to engage in a more serious substantive way,” he said.

Israeli Prime Minister Benjamin Netanyahu warned Sunday against the West being deluded into thinking Rowhani’s election marked any sort of change.

“The international community must not become caught up in wishes and be tempted to relax the pressure on Iran to stop its nuclear program,” Netanyahu told the cabinet. “It must be remembered that the Iranian ruler, at the outset, disqualified candidates who did not fit his extremist outlook and from among those whose candidacies he allowed was elected the candidate who was seen as less identified with the regime, who still defines the State of Israel [in an address last year] as ‘the great Zionist Satan.’”