Russia is supplying Iran with components for unmanned aerial vehicles and other military supplies via the Caspian Sea route. According to The New York Times, citing US officials, Moscow is helping Tehran quickly restore its offensive capabilities, as it lost approximately 60% of its drone arsenal in recent fighting. Furthermore, Russia is supplying goods that would normally pass through the Strait of Hormuz, which is currently blocked by the US Navy, helping Tehran circumvent international sanctions.

The Caspian Sea, the world's largest enclosed body of water, has become a key conduit for clandestine shipments. Only five countries—Russia, Iran, Azerbaijan, Kazakhstan, and Turkmenistan—have access to it, making the region "almost invisible" to American policymakers. Vessels traveling this route often disable tracking systems, further complicating monitoring. Nicole Grayevsky, a professor at Sciences Po University in Paris, described it as "an ideal location for circumventing sanctions and military shipments."