US National Security Advisor Jake Sullivan says the Islamic Republic could be contributing to “war crimes” in Ukraine by providing drones to Russia.

"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," Jake Sullivan told reporters on Monday.

Sullivan pointed to European and US sanctions on Iran put in place after the US exposed Islamic Republic's arms sales to Russia last year as examples of how they are trying to “make these transactions more difficult,” acknowledging that “the way that they are actually carrying them out physically makes physical interdiction a challenge. ”The US and European partners are looking to further isolate both nations in the court of public opinion, as they face challenges with physically stopping the transfers of weapons."

The United States has imposed a series of 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 mulling over ways to target the Islamic Republic’s production of the unmanned weaponized aircraft through sanctions and export controls.

Since negotiations to revive the 2015 nuclear deal or JCPOA broke down in September, the Biden administration and its European allies have put the talks on the backburner and even President Joe Biden said in early November that the “JCPOA is dead.”