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 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.

Moscow has cultivated closer ties with Iran and other nations hostile towards the U.S. since the start of the Ukraine war. It already has strategic pacts with North Korea and close ally Belarus ...

The necessity of entering into agreements with third countries to sustain the war challenges the Kremlin’s notion of military superiority.

Russian President Vladimir Putin and his Iranian counterpart, Masoud Pezeshkian, signed a broad cooperation pact Friday as their countries deepened their partnership in the face of stinging Western sanctions.

Russia and Iran have supported each other for decades — Moscow has provided support to Iran’s nuclear program, and Tehran has sent missiles and drone weapons support to Russia for its war against Ukraine. The two have also strengthened ties with China ...

Iranian President Masoud Pezeshkian and Russian President Vladimir Putin signed a 20-year strategic partnership treaty in Moscow, enhancing ties in politics, trade, security, and energy. This landmark agreement deepens collaboration between two heavily sanctioned nations and marks a pivotal shift in global alliances.

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 ...