31MAR

Putin renews HEU offer at SPIEF

3 min read

08:23UTC

Vladimir Putin restated Russia's offer to take custody of Iran's 440.9 kg highly enriched uranium stockpile at the St Petersburg forum on 6 June. It is the same arrangement Trump barred on 27 May.

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ConflictDeveloping

Key takeaway

Russia's HEU custody offer is the only live technical fix, and both Washington and Tehran have left it unanswered.

Vladimir Putin publicly restated Russia's standing offer to take custody of Iran's 440.9 kg stockpile of HEU (Highly Enriched Uranium, the 60 per cent material at the heart of the impasse) at the SPIEF (St Petersburg International Economic Forum) plenary on Saturday 6 June ¹. He added that Russia is not arming Iran, that Iran has requested no weapons, and that both the United States and Israel privately told Moscow that recent shelling near the Bushehr nuclear plant was accidental.

The custodian arrangement hands Iran a way to satisfy the US demand to remove the stockpile without surrendering it to Washington. Trump rejected precisely that arrangement at a Cabinet meeting on Wednesday 27 May, when he barred both Russia and China from the role and told his negotiators not to rush.

The offer follows Araghchi confirming no progress on the nuclear file , and it sits unanswered. Mojtaba Khamenei's order to keep the HEU inside Iran still stands, and Tehran has sent no counter-proposal since hand-editing the disputed deal text . Russia gains from being the only mediator both Washington and Tehran will still take calls from, so the offer serves Moscow's interest while remaining a concrete, deliverable route out of the deadlock.

Deep Analysis

In plain English

Iran has built up 440.9 kilograms of uranium enriched to 60 per cent purity. At 90 per cent, uranium becomes weapons-grade. The US and Israel want this stockpile removed from Iran or destroyed. Russia has repeatedly offered to take it to Russian territory for safekeeping. Putin made this offer again at SPIEF (St Petersburg International Economic Forum), Russia's annual economic conference, on 6 June. Iran's Supreme Leader has ordered the uranium stays inside Iran. As of 6 June, no custody transfer has been agreed and the war continues. Putin also said Russia is not supplying Iran with weapons, a denial that matters because US military assessments have previously linked Chinese and Russian equipment to Iran's continued military capability.

Deep Analysis

Root Causes

Russia's repeated reaffirmation of the HEU custodian offer across SPIEF (6 June), a Moscow press conference (10 May, ) and Peskov's statement (13 April, ) reflects a consistent Kremlin strategic interest: to prevent a US-Iran settlement that excludes Moscow from the regional architecture. Putin told SPIEF that 'initially everyone agreed' the uranium would go to Russia, a claim he has sole-sourced; if true, it positions the US as the party that hardened terms, not Iran.

Rosatom evacuated approximately 180 of its 200-plus staff from Bushehr by 16 April , leaving roughly 20 managers on site. Russia lacks the operational capacity to implement the custody arrangement even if Iran agreed.

Escalation

Putin's public denial that Russia is arming Iran is the most operationally significant element of the SPIEF statement. If accurate, it reduces the risk of a direct US-Russia confrontation over arms flows. The separate claim that both the US and Israel privately told Moscow the Bushehr shelling was accidental is unverifiable from the Russian side alone, but if true, it indicates an active US-Russia back-channel on escalation thresholds that has not been publicly acknowledged.

What could happen next?

Consequence
Russia positions itself as indispensable to any Iran settlement, complicating a purely US-Iran bilateral agreement.
Medium term · Assessed
Risk
Khamenei's order that the HEU stays inside Iran makes the custodian offer operationally moot until the Supreme Leader's position changes or his capacity to enforce it erodes.
Short term · Assessed
Opportunity
If Iran's economic collapse deepens, the custodian offer becomes Tehran's least-humiliating exit from the HEU impasse, enabling a deal without surrendering directly to the US.
Medium term · Reported

Source Landscape

This story draws on neutral-leaning sources

Primary parallel: The 2003-2006 Libya disarmament model, where Russia played no custodian role; Gaddafi surrendered his WMD programme directly to the US and UK after back-channel negotiations. Libya's willingness to hand material to a Western adversary is the precedent Washington wants to invoke; Tehran explicitly rejects it on the grounds that Libya was subsequently invaded.

Counter-parallel: The 1994 Budapest Memorandum, under which Ukraine surrendered its inherited Soviet nuclear arsenal to Russia in exchange for security guarantees. Russia's 2022 invasion of Ukraine is the canonical case Tehran cites when resisting any custody arrangement involving a third party.

Russia earns approximately $800m annually from the Bushehr reactor contract. Any custodian arrangement that returns Iran to IAEA compliance and lifts sanctions would reopen Iran's oil market to buyers who currently route around CENTCOM, reducing Iran's dependence on the Russia-China barter channel. Moscow benefits from Iran's economic isolation as long as it lasts; the custodian offer, if accepted, accelerates Iran's re-integration into the global economy and reduces Russian leverage.

For Iran, the $5.8bn revenue loss since April (event index 5) creates mounting pressure to accept any custody arrangement that unlocks sanctions relief. The economic pain and Putin's offer move in opposite directions on Tehran's willingness to concede.

Consensus view: Darya Dolzikova (RUSI) argues that Putin's custodian offer is structurally attractive to Iran as a face-saving device precisely because it avoids direct US custody, but is operationally undeliverable given Rosatom's evacuation of most staff from Bushehr and the physical barrier imposed by CENTCOM's blockade.

Counter-view: Fyodor Lukyanov, editor of Russia in Global Affairs and chair of the Council on Foreign and Defence Policy, has contended that Russia's real goal is to be present at any final settlement table, not to take custody; the offer is a diplomatic positioning move rather than a concrete proposal.

Key tension: Whether Mojtaba Khamenei's order that the stockpile remain inside Iran reflects a negotiating position or a constitutionally binding security doctrine that no interlocutor, including Russia, can shift.

First Reported In

Update #119 · Trump's Iran deal: 95% done, 0% signed

Press TV· 6 Jun 2026

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Causes and effects

This Event

Putin renews HEU offer at SPIEF

The one technical route out of the nuclear deadlock came from Moscow, not Washington. It lets Iran meet the US demand without conceding to Washington, which is why Trump blocked it and why Tehran has not taken it up.

Led to

Iran sends no nuclear counter to US

Putin reaffirmed the HEU custodian offer at SPIEF after Araghchi confirmed no progress on the nuclear file (ID:3887)

Occurred 4 Jun 2026

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IAEA loses track of Iran's uranium

Putin's 6 June SPIEF custodian reaffirmation is backdrop to the IAEA report making any custody clause unverifiable.

Occurred 4 Jun 2026

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US tables uranium draft at IAEA Board

Putin's SPIEF HEU custodian offer (ID:3937) is rendered unworkable alongside the US Board resolution, since the verification gap blocks any stockpile confirmation

Occurred 8 Jun 2026

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Different Perspectives

Oil traders

Sent Brent down 2.29 per cent to $98.38 a barrel on reports that mediation was reviving, moving the price on CENTCOM's quiet night rather than on Trump's same-day promise of a bigger operation with no deadline attached.

Iran

An Iranian official called the same mediation account completely misleading, denying it received any US proposal via Baghdad on the same day Iraq denied delivering one, leaving neither denial able to settle what actually passed between the two capitals.

Iraq

Called groundless the New York Times account that its prime minister carried a US ceasefire proposal to Tehran, a denial that also protects Baghdad's effort to avoid becoming a party to a war fought by aircraft it does not control.

OHCHR

Recorded 17 civilian seafarer deaths since the war began, a population neither the Pentagon nor Iran's Health Ministry counts in its own tally, and called for urgent action on 6,000 crew stranded across roughly 400 vessels in the Strait of Hormuz.

Houthis

Enforced the blockade on Saudi-linked shipping it declared on 20 July by hitting the NCC Masa and then an Aramco facility at Jazan, moving from radio warnings to strikes on land after four days without a confirmed hit.

Saudi Arabia

Struck Houthi military sites near Hodeidah the same day the NCC Masa was hit, while its coalition spokesman insisted Hodeidah, Ras Issa and Salif all remain open to navigation. The distinction protects the ports Yemen's population depends on for food and fuel even while punishing the group behind the tanker strike.