The United States is working with allies and partners to quickly impose serious economic sanctions on Moscow over bogus referendums conducted by Russia in occupied regions of Ukraine, according to a prepared statement Wednesday by the head of the U.S. State Department's sanctions coordination office, Reuters reported.

Speaking before the Senate Foreign Relations Committee, James O'Brien said he expects the pace of the Biden administration announcing sanctions against Russia every six weeks on average will continue as Washington continues to focus on bottlenecks in the Russian economy and military supply chains.