Ria Reddy, Ben Rezaei, Carolyn Moorman, Ben Schmida, Avery Borens, Johanna Moore, and Annika Ganzeveld

Information Cutoff: 2:00pm ET

Click here to view ISW–CTP's interactive control-of-terrain map of Syria.

Click here to view ISW's complete portfolio of interactive maps.

Russia continues to position itself as a mediator in the US–Iran nuclear negotiations. Russia’s mediation of the US–Iran talks would be very unlikely to secure US interests given Russia’s alignment with Iran. US President Donald Trump stated on June 4 that Russian President Vladimir Putin offered to "participate" in the US–Iran nuclear negotiations. Russia’s offer to mediate the negotiations comes after Iranian Supreme Leader Ali Khamenei explicitly rejected a recent US nuclear proposal to Iran because the proposal would require Iran to eventually halt all uranium enrichment on Iranian soil. CTP-ISW previously assessed that Iran’s continued rejection of the US demand for zero uranium enrichment could cause the US–Iran nuclear negotiations to collapse. Iran and Russia have held several meetings since March 2025 to discuss the dispute between Iran and the United States over Iran’s nuclear program. Russia has opposed stated US objectives in the nuclear negotiations and the recent US proposal by supporting Iran’s right to enrich uranium. Russian Permanent Representative to the UN in Vienna Mikhail Ulyanov claimed in early March 2025 that Iran’s production of 60 percent enriched uranium has “no weapons risk." Iran currently has enough 60 percent enriched uranium, if enriched further, to produce nearly 10 nuclear weapons. Russia’s support for Iran’s domestic uranium enrichment is inconsistent with the stated US position against uranium enrichment on Iranian soil. US President Donald Trump confirmed on June 3 that the United States maintains its position that Iran cannot enrich uranium.

Iran and Russia have deepened political and military cooperation in recent years, particularly since the Russian invasion of Ukraine in February 2022. Iran has supported Russia’s invasion of Ukraine by providing Russia with Fateh-360 ballistic missiles and launchers and Shahed drones. Iran reportedly purchased Russian Su-35 fighter jets in January 2025, though Russia has not yet delivered the Su-35s to Iran. Russia has also supported and cooperated with Iran’s Axis of Resistance in recent years. This cooperation has included working with Iran and Iranian-backed militias to attack US forces in the Middle East. Russia also supported the Axis of Resistance against Israel during the October 7 War, including by providing targeting intelligence to the Houthis to support attacks on international shipping and US vessels in the Red Sea and Gulf of Aden. Iran and Russia signed a strategic cooperation agreement in January 2025, which further illustrates their close collaboration and alignment in working to erode US global influence.

Key Takeaways:

• Russo-Iranian Cooperation: Russia continues to position itself as a mediator in the US–Iran nuclear negotiations. Russia’s mediation of the US–Iran talks is unlikely to secure US interests given Russia’s alignment with Iran. Russia has opposed stated US objectives in the nuclear negotiations and the recent US proposal by supporting Iran’s right to enrich uranium. Russian Permanent Representative to the UN in Vienna Mikhail Ulyanov claimed in early March 2025 that Iran’s production of 60 percent enriched uranium has “no weapons risk." Iran currently has enough 60 percent enriched uranium, if enriched further, to produce nearly 10 nuclear weapons.

• Iranian Efforts to Undermine Sanctions: Iran is leveraging its membership in multilateral organizations such as BRICS and the Shanghai Cooperation Organization (SCO) to try to mitigate the effects of international sanctions. Iranian Parliament Speaker Mohammad Bagher Ghalibaf attended the 11th BRICS Parliamentary Forum in Brazil on June 4 and 5. Ghalibaf called for a joint legislative charter among BRICS members to counter sanctions. Iranian Central Bank Governor Mohammad Reza Farzin separately attended a meeting for central bank governors of Shanghai Cooperation Organization (SCO) member states in Beijing on June 2. Farzin proposed the creation of a joint bank for SCO member states in order to facilitate financial transactions among members and reduce reliance on institutions such as the International Monetary Fund and the World Bank.

• Iranian Preparations for a Potential Strike: Senior Iranian military commanders continue to prepare for potential US or Israeli strikes on Iran. Khatam ol Anbia Air Defense Headquarters Commander Brigadier General Alireza Sabahi Fard inspected Iran's Northern Air Defense Zone at Mehrabad Airport in Tehran Province on June 5 to evaluate military units and defense capabilities at the site. Sabahi Fard also inspected air defense positions near former Supreme Leader Ruhollah Khomeini’s mausoleum in southern Tehran. Sabahi Fard may have inspected the Hazrat-e Amir Brigade Air Defense Site.

• Syria and Lebanon Cooperation: Syria and Lebanon have continued to dismantle likely Iranian-linked weapons smuggling networks along the Syria-Lebanon border. Syrian forces have interdicted at least two weapons shipments in Homs Province en route to Lebanon since May 29.

Click Here to Read the Full Update

Website | Jobs & Internships

Follow ISW on social media:

Facebook | X | YouTube | Instagram | LinkedIn | Threads | Bluesky

Donate online or by sending a check to the Institute for the Study of War at 1400 16th Street NW, Suite #515, Washington, DC, 20036. Please consider including the Institute for the Study of War in your estate plans.

ISW is a tax-exempt organization under section 501(c)(3) of the Internal Revenue Code. Donations are tax-deductible to the extent permitted by law.

The Institute for the Study of War (ISW) is a non-partisan, non-profit, public policy research organization. ISW advances an informed understanding of military affairs through reliable research, trusted analysis, and innovative education. We are committed to improving the nation's ability to execute military operations and respond to emerging threats in order to achieve US strategic objectives.