Russia's upper house of parliament ratified a sweeping 20-year strategic partnership agreement with Iran on Wednesday, deepening military and nuclear cooperation just as fears of conflict between Washington and Tehran intensify.The Russian Federation Council confirmed the deal's ratification following a session in Moscow, advancing a pact signed in January by Russian President Vladimir Putin and Iranian President Masoud Pezeshkian. The agreement paves the way for expanded defense coordination and signals Moscow's backing for Tehran amid heightened tensions with the United States.Newsweek reached out to the Kremlin and Iran's foreign ministry for comment.Why It MattersThe agreement comes as the U.S. and Iran are locked in nuclear negotiations brokered by Oman. President Donald Trump has revived his "maximum pressure" campaign and warned Iran must never obtain a nuclear weapon. With Iran refusing to end uranium enrichment and Washington hinting at military options, the ratified Russia-Iran deal may complicate U.S. decision-making in the region by raising the prospect of Russian involvement in any future conflict.What To KnowAccording to the Federation Council's statement, the agreement outlines long-term cooperation in areas including arms control, counterterrorism, peaceful nuclear energy, and security coordination at regional and global levels. It also includes a clause stipulating that the other will not aid the aggressor if either country is attacked.Meanwhile, Kremlin spokesman Dmitry Peskov said that Russia is prepared to do "everything" to help resolve the standoff between the U.S. and Iran.Message for PutinElsewhere, Iranian Foreign Minister Abbas Araghchi announced he will deliver a written message from Supreme Leader Ayatollah Ali Khamenei to Putin during an official visit to Moscow, saying the message would be conveyed during a scheduled meeting with the Russian leader, according to state media.U.S. Hardline ShiftOn Tuesday, U.S. Special Envoy Steve Witkoff announced a hardline shift in policy, stating that any agreement with Iran must include the complete elimination of its uranium enrichment and weaponization programs. White House press secretary Karoline Leavitt reinforced the stance, saying, "The maximum pressure campaign on Iran continues," and emphasized that Trump has made clear Iran must never be allowed to obtain a nuclear weapon.What People Are SayingKremlin spokesperson Dmitry Peskov told reporters: "The Russian Federation remains ready to do everything within our capabilities to contribute to the settlement of the situation by political and diplomatic means."Iran Foreign Minister Abbas Araghchi said: "The purpose of my trip to Russia is to convey the Leader's written message to Putin, which will be delivered during a meeting with him."Negar Mortazavi, senior fellow at the Center for International Policy and host of The Iran Podcast told Newsweek: "Iran is under extreme economic pressure from Western sanctions and sees itself under serious military threats from Israel and potentially the U.S. So they are increasingly relying on Eastern powers, China and Russia, even more than before."What Happens NextAs the next round of Iran-U.S. talks approaches, the Russia-Iran pact could alter the geopolitical calculus, potentially deterring military escalation and hardening Tehran's negotiating stance.