WASHINGTON — Iran and the United States are making plenty of friendly gestures, but real progress is going to be harder. A notable first meeting between the two nations’ presidents suddenly seems possible next week, but without nuclear concessions the U.S. is unlikely to give Tehran what it wants: an easing of punishing sanctions that have resulted in soaring inflation and unemployment.

President Barack Obama and Iran’s new president, Hasan Rouhani, both will be in New York next week for the United Nations General Assembly. And a recent flurry of goodwill gestures has raised the prospect that they will meet face to face.

Pleasantries aside, however, the U.S. and other world powers are seeking reductions in Iran’s uranium enrichment, real-time monitoring of its nuclear facilities and scaled-back production at its underground Fordo facility. Not likely, Iran experts say. At least not yet.

“I’m a bit skeptical that we’ll see those kinds of concessions this early in the game,” said Gary Samore, who until earlier this year was Obama’s top arms control adviser.

The Obama administration has welcomed the election of Rouhani, a moderate cleric who achieved a stunning victory in Iran’s June presidential elections. And upbeat signals have suggested there could be talks between Obama and Rouhani on the U.N. sidelines.

But U.S. officials are still skeptical of whether Rouhani’s more palatable rhetoric will be followed by actual shifts in Iran’s longstanding refusal to curb its nuclear program. The U.S. and its allies suspect Iran is trying to produce a nuclear weapon, though Tehran insists its nuclear activities are only for producing energy and for medical research.

Obama has been testing the waters through an exchange of letters with his Iranian counterpart. U.S. officials say Obama used his correspondence to convey urgency in resolving the nuclear dispute through diplomacy before that option is cut off. Rouhani, in an interview with NBC News, said he thanked Obama for his outreach and “expressed Iran’s viewpoint on the issues raised in his letter and some other issues.”

Rouhani has made other overtures that have grabbed the Obama administration’s attention. He included Iran’s only Jewish lawmaker in his delegation to the United Nations meeting. And the Iranian government this week released a dozen prominent political prisoners, including a human rights lawyer who defended opposition activists and was imprisoned for three years.

White House officials said Friday that no meetings between Obama and Rouhani are currently scheduled, but they left open the prospect of a direct exchange.

“We’re always open to diplomacy if we believe it will advance our objectives,” said Ben Rhodes, Obama’s deputy national security adviser.

An face-to-face meeting between Obama and Rouhani would mark a significant step in the U.S.-Iranian relationship. But the real work on the nuclear issue would come either from direct negotiations between U.S. and Iranian officials or renewed talks between Iran and six world powers— the U.S., Russia, China, Britain, France and Germany.

Those negotiations have stalled largely because of disagreements over Iran’s right to enrich uranium, even at low levels that would cut off their capability to build a nuclear bomb. Iran wants the international community to acknowledge its right to enrich under the Non-Proliferation Treaty, but the six negotiating countries have shied from doing so.

Among Iran’s primary concerns in negotiations is securing the removal of crippling international economic sanctions, while accepting as few constraints as possible on its nuclear program. The Obama administration, however, sees the sanctions as a key lever of power and is reluctant to ease the penalties.

“We believe that the most stringent sanctions regime we’ve ever put in place against the Iranian government is part of why we are here today with this opportunity for diplomacy,” State Department spokeswoman Marie Harf said Friday.

The diverging views on sanctions and enrichment capabilities stymied negotiations with Iran earlier this year, when the parties considered a proposal for Tehran to reduce its uranium reduction to 5 percent.

That’s a level the U.S. and its partners say would let Tehran continue legitimate nuclear activities and help build global confidence that it is committed to its pledge that it will not build an atomic bomb. However, the Iranians wanted the U.S. to significantly ease economic sanctions in exchange, said Samore, who is now at Harvard University’s John F. Kennedy School of Government.

Samore said the world powers were open to only a modest easing of sanctions — and only if Iran agreed to the reduction, plus halting production and limiting its stockpiles of 20 percent enriched uranium. That’s the highest grade of enrichment that Iran has acknowledged and one that experts say could be turned into a nuclear warhead grade in a matter of months.

U.S. officials have also said that enrichment would need to be suspended at Iran’s underground Fordo nuclear facility southwest of Tehran, and its stockpile of high-grade uranium be moved out of the country. Iran acknowledged in 2009 that it was building the bunker-like plant — but only after U.S. intelligence revealed it to the International Atomic Energy Agency.

The facility is located on an Iranian military base, and it was built to hold about 3,000 centrifuges — which a senior U.S. official said is the amount needed to build nuclear weapons.

Fordo compounded the general distrust of Iran’s program and fueled concerns that international monitors do not have an up-to-the-moment understanding of activities at nuclear sites around the country.

Robert Einhorn, who was one of the U.S. negotiators until he left the State Department in May, said world powers may also demand that remote hook-ups be placed at Fordo or other plants “so that the first time Iran broke the seals on any stored material, that would immediately go to some monitor in IAEA headquarters.”

However, Einhorn warned: “These Iranians are not going to be pushovers in the negotiations.”