It would take effect alongside the European Union’s next batch of sanctions, which include a ban on seaborne imports of Russian oil starting in early December.
Russia had already threatened to retaliate by banning oil exports to countries that implement a price cap.
The Biden administration has been pushing for governments to introduce a price cap for months.
The price at which Russian oil will be capped still needs to be hashed out.
But the US Treasury official noted they would be more expensive, raising incentives for buyers to opt in to the price cap system.