Iran would signal a "dramatic escalation” of support for Russia by providing ballistic missiles to aid its war in Ukraine, Central Intelligence Agency Director William Burns said.

Burns and his U.K. counterpart, Richard Moore, warned during a joint appearance in London that military cooperation between the two countries is deepening.

Bloomberg reported Friday that Iran sent ballistic missiles to Russia, defying months of warnings by U.S. and European officials. At a Financial Times event in London on Saturday, Burns declined to confirm that the transfer had taken place.