The United States is in talks with Iran to draw up steps that could lead to curbing its nuclear program, releasing some detained U.S. citizens and ending the freeze on some Iranian assets abroad.

Western and Iranian officials have unveiled the talks, and these steps can be described as an "understanding" rather than an agreement that requires review from the US Congress, according to the Reuters news agency, which noted that many members of Congress oppose granting Iran advantages because of what they call "its military assistance to Russia, its repressive actions at home and its support for proxies attacking US interests in the region."

State Department spokesman Matt Miller denied there was any deal with Iran, but said Washington wanted Tehran to ease tensions, curb its nuclear program, stop supporting groups in the region carrying out proxy attacks, stop supporting Russia's war on Ukraine and release detained U.S. citizens.

"We continue to use diplomatic means of communication to achieve all of these goals," Miller said, without elaborating.

"Call it what you want, whether it's an interim agreement, an interim agreement or a common understanding, both sides want to prevent further escalation," an Iranian official said.

Initially, "this will include a prisoner exchange and the release of part of the frozen Iranian assets", he said.

Other steps could include waivers from Iran-linked U.S. sanctions on oil exports in exchange for halting uranium enrichment at 60 percent and greater Iranian cooperation with the U.N. nuclear watchdog, he said.

Understanding calm

The U.S. special envoy for Iran met with Iran's ambassador to the United Nations, Rob Malley, months after Tehran refused direct contact.

"I can call it a calming understanding," said a Western official, speaking on condition of anonymity, adding that there had been more than one round of indirect talks in Oman between U.S. National Security Council official Brett McGurk and Iran's chief nuclear negotiator Ali Bagherikani.

The Western official explained that the idea is to create a status quo acceptable to all, and to make Iran avoid the western red line of enriching uranium to 90 percent purity, a stage that is usually seen as a type of weaponization.

In addition to halting enrichment at 60 percent, the two sides are considering more Iranian cooperation with the IAEA and not installing more advanced centrifuges in exchange for a "significant transfer" of Iranian funds abroad, the official said.

Pressure and criticism

In contrast, the chairman of the US House Foreign Affairs Committee, Michael McCaul, sent a letter to President Joe Biden expressing concern about the recent revelations that the administration is seeking a new nuclear deal with Iran. McCaul added that instead of using diplomatic leverage and military deterrence to dissuade Iran from engaging in what he called malign activities, this administration is rewarding Tehran's bad behavior in exchange for a false promise of de-escalation.

For his part, British Minister for the Middle East Tariq Ahmed said that Iran has violated its obligations to the nuclear deal by increasing its uranium enrichment, and the British minister urged in a statement to Al Jazeera Tehran to abandon what he described as malign activities destabilizing the region and stop its support for the Russian war on Ukraine.

After failing to revive the 2015 Iran nuclear deal, Washington hopes to restore some restrictions on Iran to prevent it from obtaining a nuclear weapon that could threaten Israel and spark an arms race in the region, while Tehran says it does not aspire to develop a nuclear weapon.

The 2015 deal, which former U.S. President Donald Trump withdrew from in 2018, put an end to Tehran's enrichment of uranium at 3.67 percent purity and its stockpile of uranium at 202.8 kilograms, limits Tehran has since exceeded in response to the U.S. withdrawal from the deal.