The sources did not provide specific details regarding the number of weapons and the timing of the transfers, but they confirmed that the US intelligence has made the finding.

While the White House declined to confirm the weapons transfer, it reiterated its concern over Iran's increasing support for Russia. For months, the White House has been warning Iran against transferring ballistic missiles to Russia, highlighting the potential consequences for Ukrainian civilians and European security.

National Security Council spokesman Sean Savett stated, "Any transfer of Iranian ballistic missiles to Russia would represent a dramatic escalation in Iran's support for Russia's war of aggression against Ukraine and lead to the killing of more Ukrainian civilians. This partnership threatens European security and illustrates how Iran's destabilizing influence reaches beyond the Middle East and around the world."

The US intelligence discovery comes at a time when the Kremlin is facing Ukraine's unexpected offensive, resulting in the seizure of approximately 500 square miles (1,300 kilometers) of Russia's Kursk region. Concurrently, Ukraine's president, Volodymyr Zelenskyy, is urging allies to allow the use of Western-supplied missiles to strike deep inside Russia and target sites from which Moscow conducts aerial attacks.

Iran, as it has done in the past with similar intelligence findings, has denied providing weapons to Russia for the conflict in Ukraine. In a statement from Iran's mission to the United Nations, they claimed that any military assistance causing increased casualties and destruction was deemed inhumane, denying their involvement and urging other countries to cease supplying weapons to the conflict parties.

CIA Director William Burns, during a joint appearance with his British intelligence counterpart in London, expressed concern about the growing and troubling defense relationship involving Russia, China, Iran, and North Korea. He warned that this alliance posed a threat not only to Ukraine but also to Western allies in the Middle East.

The White House has been consistently declassifying and publicizing intelligence findings, highlighting North Korea's ammunition and missile supply to Russia for use against Ukraine. Additionally, Iran has provided attack drones to Moscow and assisted in the establishment of a drone manufacturing factory. China, although refraining from providing weapons directly, has increased sales of technology and equipment to Russia, enabling them to produce missiles, tanks, aircraft, and other weaponry.

The US administration has been apprehensive for months about a potential deal between Iran and Russia. While it was stated in January that a Russian-Iranian deal had not been finalized, concerns remained regarding the progress of negotiations for missile acquisitions. Last September, Iran showcased various ballistic missile systems to a top Russian defense official, further fueling American worries about a potential deal.

In response, the US and other countries have implemented measures aimed at thwarting the supply, sale, or transfer of ballistic missile-related items involving Iran. They have issued guidelines to private companies to ensure that inadvertent support for Iran's development efforts is prevented.

President Joe Biden is scheduled to meet with British Prime Minister Keir Starmer at the White House on Friday, where "continuing robust support to Ukraine in its defense against Russian aggression" will be on the agenda, according to White House press secretary Karine Jean-Pierre.

The US intelligence finding, first reported by The Wall Street Journal, underscores the ongoing concerns over Iran's support for Russia in the conflict in Ukraine and the broader implications for regional stability and global security.