The European Union's top diplomat on Tuesday called for an international nuclear deal with Iran along the lines of a 2015 agreement, days after US President Donald Trump mooted military action to dismantle it.
High Representative Kaja Kallas's remarks signal an important policy statement by the bloc after Washington and Tehran jousted over whether the so-called Joint Comprehensive Plan of Action (JCPOA) from which Trump withdrew in his first term can be a basis for a renewed agreement.
"The constant expansion of Iran’s nuclear programme fully contradicts Iran’s own commitments as endorsed by the Security Council," Kallas said at a United Nations Security Council session on EU-UN cooperation.
"At the same time, a multilateral approach, like the JCPOA was, is key. There is no sustainable alternative to a diplomatic solution."
Iran denies seeking a nuclear weapon but the UN's nuclear watchdog last week pointed to a sharp rise in Tehran's stockpile of highly enriched uranium.
The United States and European Union said Iran's activities serve no credible civilian purpose and demanded it immediately desist.
Trump said on Thursday that Tehran would need to ditch a nuclear program much of the West views as a precursor to building nuclear weapons or face military force.
The hawkish US president has not specified whether the JCPOA, from which he withdrew in his first term after bashing it as too lenient, would be the basis of the talks or whether he sought any international buy-in for a new deal.
Rejecting the idea of a renewed agreement, the Revolutionary Guards' Tasnim news agency said a deal already existed in the form of the JCPOA.
Iran's ally Russia has said it is willing to mediate and Moscow's envoy to the UN nuclear watchdog said on Monday that the JCPOA remains the essential foundation for any future negotiations on Iran's nuclear program.
Kallas went on to criticize Iran's aid to Russia in its full-scale invasion of Ukraine.
"Russia has brought others – North Korea, Iran – to support its colonial battle too."
"Iran’s military support to Russia, including the delivery of ballistic missiles, is a major threat to international security," she added.
Bruised by its falling out with Europe and feeling encircled by US-led sanctions, Moscow is likely to act as a spoiler, neither allowing its Mideast ally to be decisively weakened nor fully insulated from Western demands over its nuclear program.
Russia said this week that it seeks an agreement along the lines of an international nuclear deal in 2015 it signed onto along with the United States, signaling it might join the effort to press Tehran on its escalating nuclear enrichment.
The remarks may suggest Moscow believes Iran might limit its nuclear activities in exchange for sanctions relief.
Russia has a vested interest in preventing this issue from escalating into a full-blown crisis. Moscow sees Iran’s economic collapse—driven by US sanctions and chronic mismanagement—as a liability, weakening Tehran’s regional influence.
Iran’s diminishing ability to project power in Syria and Iraq threatens Russia’s own strategic foothold, particularly in Syria, where it has invested heavily. A destabilized Iran could also complicate Russia’s broader geopolitical maneuvers, including its efforts to counter Western influence in the Middle East.
Leave Iran in limbo
Russia benefits from an Iran that is economically viable but not fully reintegrated into the global system—dependent enough on Moscow to remain aligned, yet stable enough to prevent regional turmoil.
Iran is desperate for sanctions relief, but is unlikely to fully abandon its nuclear ambitions, which it views as a core element of national security. It could be persuaded by Russia, however, to limit certain aspects of its nuclear program in exchange for economic concessions without fully relinquishing its capabilities.
However, Supreme Leader Ali Khamenei remains firm in his opposition to direct negotiations with the US, a stance rooted in ideology and mistrust.
In 2013, his policy of “heroic flexibility” allowed for the eventual deal to come about in 2015—the Joint Comprehensive Plan of Action (JCPOA), as it’s known officially. But the context has since shifted. Trump’s withdrawal from the deal in 2018 as well as Iran’s deepening reliance on Russia and China have hardened his position.
Any renewed talks would require guarantees that Iran is unlikely to trust, making a diplomatic breakthrough more difficult.
Avoiding war
Meanwhile, Western powers are increasingly considering a snapback of UN sanctions in the next few months. That could escalate tensions to the point of military confrontation—particularly with Israel, which has consistently warned that it will not allow Iran to develop nuclear weapons.
A direct conflict involving Israel and the U.S. would not only destabilize the region but also undermine Russia’s influence, disrupt energy markets, and divert global attention from Moscow’s priorities, including its war in Ukraine.
Russia’s actual ability to mediate between Iran, Israel, and the U.S. is hard to gauge. US president Donald Trump says he has a good relationship with Russian counterpart Valdimir Putin, which can be a positive.
Israeli prime minister Benjamin Netanyahu is on good terms with Putin too. Although the relationship has been complicated with Moscow's growing military and economic partnership with Tehran, the Kremlin may still be in a position to discourage Tel Aviv from full-scale military action.
Ultimately, Russia’s interest lies in preventing an uncontrolled escalation that could disrupt its strategic ambitions. Moscow does not seek to resolve the Iran nuclear crisis but to manage it—keeping tensions high enough to maintain leverage over both Iran and the West while avoiding outright war.