The United States has been in touch with European allies on reports that Iran is "planning to deliver hundreds of ballistic missiles to Russia," State Department spokesman Vedant Patel told reporters.

"We are prepared to deliver a swift and severe response if Iran were to move forward with the transfer of ballistic missiles, which would, in our view, represent a dramatic escalation in Iran's support for Russia's war of aggression against Ukraine," he said.

Russia has been turning to countries under international sanctions, including North Korea, for military equipment to support its operations in Ukraine.

Reuters claimed on Firday, citing two European intelligence sources, that dozens of Russian military personnel are being trained in Iran to use the Fath-360 close-range ballistic missile system, adding that they expected the imminent delivery of hundreds of the satellite-guided weapons to Russia.

Iran’s UN representative has denied Reuters’s report. "Legally, Iran has no restrictions or prohibitions on buying or selling conventional weapons. But morally, Iran will avoid transferring any weapons, including missiles, that may be used in the conflict with Ukraine until it ends," Iran’s UN representative said. 

The United States has previously imposed sanctions on suppliers of Iranian drones, or unmanned aerial vehicles (UAVs), to Russia.

"Iranian officials also continue to deny providing any UAVs to Russia when evidence is plain for the world to see that Russia has used these UAVs in relentless attacks against the civilian population in Ukraine, against civilian infrastructure," Patel said.

He noted that Iranian President Masoud Pezeshkian considered a reformist, had campaigned with hopes of improving relations with the United States and European countries.

Early this year, Iran hinted at a decisive and immediate response to any US threat to attack its territory, and Foreign Minister Hossein Amirabdollahian called then on the Joe Biden administration to stop using the language of threat and focus on political solutions.

Iran's Revolutionary Guard Corps (IRGC) commander Hossein Salami said back then "enemies raise the threat and nowadays we hear some threats in between words by US officials."

"We tell them that you have experienced us and we know each other. We do not leave any threat without an answer."

* This story has been edited by Ahram Online.