US National Security Adviser Jack Sullivan confirmed - on Saturday - that a Russian delegation visited Tehran at least twice this summer, in order to inspect the combat drones that Tehran will deliver to Moscow.
The Iranian army showed its drones to Russian officials on July 5 and 8 at the Kashan air base, 200 km south of Tehran, according to satellite images revealed by the US government.
"We are publishing these photos taken in June that show Iranian drones that were seen by the Russian delegation that day, and this indicates the continued Russian interest in acquiring Iranian combat drones," Sullivan said.
"As far as we know, this is the first time that a Russian delegation has visited this air base for such a purpose," he added.
And the White House announced - Monday - that it had received information that Iran was preparing to supply Russia with hundreds of drones, including combat ones, and that the Iranian army would conduct training courses for the Russians to deal with these weapons starting in July.
For his part, US National Security Council spokesman John Kirby told CNN this week that these drones can be used for reconnaissance and munitions delivery.
"It was important to inform the world that we knew that Russia needed this additional capacity," Kirby said, noting that they were "acceleratingly increasing their resources."
On Friday, Iranian Foreign Minister Hossein Amir Abdollahian, in a phone conversation with his Ukrainian counterpart Dmytro Kuleba, denied the White House's assurances of delivering drones to Russia, describing them as "baseless."
Drones constitute a crucial weapon in the ongoing battles between the Russian army and Ukrainian forces, and artillery bombardments help identify enemy targets, carry out reconnaissance missions and carry out targeted strikes.
Last year, the Iranian Revolutionary Guard revealed a drone, dubbed "Gaza".
Iran's development of unmanned aircraft raises the concern of both the United States and Israel, which accuse Tehran of providing its allies in the Middle East with these aircraft, or using them to target American forces and navigation in the Gulf.