JEDDAH, Saudi Arabia July 16 (Reuters) - 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.

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.

On Friday, Iran's Foreign Minister Hossein Amirabdollahian, in a phone call with his Ukrainian counterpart, rejected as baseless U.S. accusations about Iranian drones being sent to Russia for use in the war against the Ukraine.

Iran, which has supplied UAVs to its allies in the Middle East, on Friday announced its first naval drone-carrying division in the Indian Ocean as U.S. President Joe Biden visits the Middle East.

Biden is expected to meet with Arab leaders in Saudi Arabia on Saturday and discuss integrating missile and defence capabilities in the region to combat Iranian drone and missile attacks in the Middle East.

"Russia is effectively making a bet on Iran and we are making a bet on a more integrated, more stable, more peaceful and prosperous Middle East region," a senior U.S. administration official told reporters on Saturday.

Biden has used Iran's growing ties with Russia as a rallying cry to press Arab countries to take a harder stance on the Ukraine crisis. Gulf nations, which have energy and business ties with Moscow, have so far refused to take sides.