(CNN) A Russian delegation has visited an airfield in central Iran at least twice in the last month to examine weapons-capable drones, according to national security adviser Jake Sullivan and satellite imagery obtained exclusively by CNN.
Iran began showcasing the Shahed-191 and Shahed-129 drones, also known as UAVs or Unmanned Aerial Vehicles, to Russia at Kashan Airfield south of Tehran in June, US officials told CNN. Both types of drones are capable of carrying precision-guided missiles.
"We have information that the Iranian government is preparing to provide Russia with several hundred UAVs, including weapons-capable UAVs," Sullivan told CNN in a statement.
"We assess an official Russian delegation recently received a showcase of Iranian attack-capable UAVs," Sullivan added. "We are releasing these images captured in June showing Iranian UAVs that the Russian government delegation saw that day. This suggests ongoing Russian interest in acquiring Iranian attack-capable UAVs."
Sullivan said that to the US' knowledge, the June visit "was the first time a Russian delegation has visited this airfield for such a showcase." A Russian delegation visited the airfield for a similar showcase again on July 5, the officials said.
The news comes as Biden is wrapping up his trip to the Middle East, where Iran was a key point of discussion among the US, Israel, Saudi Arabia and the Gulf countries. A US official told CNN that the growing partnership between Iran and Russia exemplifies why the US needs to maintain its presence and influence in the Middle East.
Biden remains under increasing pressure from Middle Eastern allies to come up with a viable plan to constrain Iran, as hopes for reviving the 2015 nuclear deal have faded following stalled talks in Doha, Qatar, last month.
White House officials revealed earlier this week that newly declassified US intelligence indicates that Iran is expected to supply Russia with "hundreds" of drones for use in the war in Ukraine, with Iran preparing to begin training Russian forces on how to operate them as early as late July.
Russia, the US now believes, has apparently turned to Iran to help replenish its drone stockpiles. It is unclear how sophisticated or effective those drones will be, however.
Russia had previously turned to China for help in supporting its war in Ukraine, US officials disclosed in March. As of late May, the US had seen no evidence that China had provided any military or economic support to Russia for the invasion, Sullivan told reporters at the time.