The Biden administration has allowed a series of sanctions waivers that permit Iran and Russia to engage in joint nuclear work to lapse but won't commit to enforcing those sanctions, sowing confusion about U.S. policy at a time when both countries are building out Tehran's atomic infrastructure.

The waivers, which were last renewed in August 2023, expired at the beginning of 2024. They provided upwards of $10 billion in profit for Russian-state controlled firms, such as the Rosatom energy company, for work at Iran's various nuclear plants, including contested military sites suspected of housing the country's atomic weapons program.

Yet the Biden administration will not commit to enforcing those sanctions now that the waivers have expired. A State Department spokesman would not say why the waivers were allowed to expire and told the Washington Free Beacon that officials are still "reviewing the waiver as part of the regular review process" and that a public comment will only be given "once a decision is made as part of that review." The response is fueling questions on Capitol Hill as Iran advances plans to invest at least $50 billion in its Russian-made nuclear plants.