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.

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,

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.

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 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 signed a new strategic cooperation pact as the two countries brace for the return of U.S. President-elect Donald Trump to the White House.

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

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.

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

Analysis: The 20-year strategic agreement bolsters bilateral ties as Russia and Iran reel from the loss of the Syrian regime, but frictions remain.

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