WASHINGTON

Iran is moving rapidly to provide Russia with hundreds of its domestically-manufactured drones to bolster the Kremlin's war effort against Ukraine, a senior Biden administration official said Monday. 

Jake Sullivan, President Joe Biden's national security adviser, said the US has information suggesting Tehran "is preparing to provide Russia with up to several hundred UAVs, including weapons-capable UAVs, on an expedited timeline." He was referring to unmanned aerial vehicles, or drones.

Iran, Sullivan said, is further preparing to train Russian forces on its drones as soon as this month as Moscow's forces continue to suffer battlefield losses amid its slowly grinding offensive in eastern Ukraine.

Sullivan did not specify the intelligence on which he was basing his claims.

The US and its Western allies have worked to implement sweeping sanctions on Russia, in part to prevent the country from replenishing its war stocks. That has included imposing export restrictions on key dual-use technologies, including drones.

DJI, a China-based leader in drone technologies, announced in April that it would suspend its operations in Russia due to Western sanctions that were imposed in retaliation for Russia's war.

Sullivan said Iran's decision to send drones to Russia is further proof that Moscow's war stocks have been badly depleted by its war in Ukraine and its gains in the country's east have come "at a cost to the sustainment of its own weapons."

Iran provided similar unmanned weapons to Yemen's Houthi rebels before a cease-fire agreement was reached earlier this year, Sullivan said.