NICOLE GRAJEWSKI is a Fellow in the Nuclear Policy Program at the Carnegie Endowment for International Peace and an Associate with the Project on Managing the Atom at the Harvard Kennedy School. She is the author of Russia and Iran: Partners in Defiance From Syria to Ukraine.

Russia and Iran signed a mutual defense and security cooperation pact on Jan. 17 — just days before President Trump’s inauguration. Both nations are primary opponents of the U.S., demonstrated by Russia’s war against Ukraine and Iran’s attempts to assassinate Trump,

Iran has purchased Russian-made Sukhoi-35 fighter jets, a senior Revolutionary Guards commander said on Monday, amid Western concerns about Tehran and Moscow's growing military cooperation.

The presidents of Russia and Iran have held talks in the Kremlin before the signing of a broad cooperation pact to deepen their partnership amid stinging Western sanctions.

Russian President Vladimir Putin and his Iranian counterpart Masoud Pezeshkian deepened military ties between their countries on Friday by signing a 20-year strategic partnership that is likely to worry the West.

The agreement is focused more on trade than military issues, but it will bring two countries with a shared desire to challenge the West closer together.

While Moscow and Tehran have shared warmer relations for decades, a revival of the nations’ allyship occurred when the former invaded Kyiv.

Iran and Russia signed a 20-year strategic partnership treaty. It outlines significant economic and military cooperation.

Russian President Vladimir Putin and Iranian President Masoud Pezeshkian signed a broad cooperation agreement, deepening their already growing partnership.

Russian President Vladimir Putin and his Iranian counterpart Masoud Pezeshkian held talks in Moscow on Friday ahead of the signing of a strategic partnership treaty involving closer defense cooperation that is likely to worry the West.

Russia and Iran signed a new treaty on Friday underpinning their economic and military cooperation, in what both sides cast as a major milestone in their relations.

Russia and Iran were the main military allies of Syrian President Bashar al-Assad, who fled to Moscow after being toppled last month. The West also accuses Iran of providing missiles and drones ...