The United States believes that Russian officials visited an airfield in Iran recently to view attack-capable drones, U.S. national security advisor Jake Sullivan said on Saturday, News.az reports citing CNN.

The United States earlier this week said it has information that shows Iran is preparing to provide Russia with up to several hundred drones, including some that are weapons capable, and that Tehran is preparing to train Russian forces to use them. Iran's foreign minister denied that.

"We assess an official Russian delegation recently received a showcase of Iranian attack-capable UAVs....To our knowledge, this is the first time a Russian delegation has visited this airfield for such a showcase," Sullivan said in a statement.

The statement included satellite imagery dated June 8 showing Iranian unmanned aerial vehicles (UAVs) "that the Russian government delegation saw that day". It said similar equipment was showcased for a second Russian visit to the airfield on July 5.