Iran could be contributing to war crimes in Ukraine by providing drones to Russia, White House national security adviser Jake Sullivan said on Monday.

"Their weapons are being used to kill civilians in Ukraine and to try to plunge cities into cold and darkness which, from our point of view, puts Iran in a place where it could potentially be contributing to widespread war crimes," Sullivan told reporters during a trip by President Joe Biden to Mexico.

The United States has imposed sanctions on companies and people it accused of producing or transferring Iranian drones that Russia has used to attack civilian infrastructure in Ukraine.

The White House said last week that the United States is also considering ways to target Iran's production of the unmanned weaponized aircraft through sanctions and export controls.