The US is pressuring Iran to cease its sale of armed drones to Russia in exchange for easing sanctions on Tehran, sources familiar with the matter have told the Financial Times.

The US move is part of a broader, unwritten understanding between the Washington and Tehran aimed at de-escalating tensions and addressing the longstanding nuclear issue between them. For the US this would also strike a blow to Russia’s military campaign in Ukraine.

The Biden administration, led by its specific “Iran team”, has reportedly broached the topic with the clerical leadership in Tehran during ongoing indirect talks in Qatar and Oman.

These talks have occurred concurrently with negotiations on a prisoner exchange deal. Last week, as a result, Tehran transitioned four Iranian-US citizens from prison to the Espinas Palace Hotel in the north of city.

"The move of our detainees out of prison and to home detention is not linked to any other aspect of our Iran policy," US Secretary of State Antony Blinken stated on August 15.

He emphasised the US' strategy of "deterrence, pressure, and diplomacy" to prevent Iran from acquiring nuclear weapons and to hold them accountable for human rights violations and supplying drones to Russia for use in Ukraine.

According to an unnamed Iranian official and another individual briefed on the matter, the US is concerned about Iran's provision of drones and spare parts to Russia, which are being utilised in the ongoing conflict in Ukraine.

While Iran has officially denied its drones' involvement in Ukraine, Tehran has reportedly urged Moscow to refrain from using them. However, the US is seeking more definitive actions in the form of incentives.

The indirect talks aim to achieve mutual de-escalatory measures. For Iran, this would involve commitments such as not enriching uranium beyond 60% purity, enhancing cooperation with the International Atomic Energy Agency (IAEA), and ensuring Americans are not targeted. In exchange, the US would potentially ease certain sanctions, especially those related to oil sales, while maintaining strictures related to human rights.

The Islamic Republic is also urging the US to persuade European allies to reduce pressures, given the economic strain from US sanctions implemented after the 2015 nuclear accord was abandoned by former US President Donald Trump.

Despite reaching a consensus on several issues, the talks facilitated through intermediaries will continue, especially concerning Russia, the Iranian official noted.

A Western diplomat expressed caution, highlighting the challenges of ensuring the entire Iranian system's compliance with any agreed-upon measures.

As part of the discussed exchange, Iran would release five US prisoners, while the US would free five Iranians.

Additionally, the US would permit Tehran to access $6bn in frozen oil funds transferred from South Korea to Switzerland and then on to Qatar, where Iranian banks will have access to the money.

Political watchers in Tehran remain cautious of the latest closed-door negotiations between Tehran and Washington due to the several failed starts and the impending US election in 2024, which could potentially see Donald Trump back in the White House.

Speaking with bne IntelliNews, one person who previously worked in Tehran said: “To be honest, I don’t expect much from this latest half-deal, Iran’s position remains limited, and any benefits are likely to be kiboshed by third parties who look to keep the Iranian economy offline.”