U.S. prepared to impose more costs on Russia over Ukraine referendums

The United States is prepared to impose additional economic costs on Russia in conjunction with U.S. allies if Moscow moves forward with Ukraine annexation, the White House said on Friday.

Russia has been planning what Washington describes as sham referendums in portions of eastern Ukraine in what is seen as a step toward annexing these territories.

"We know that these referenda will be manipulated," said White House press secretary Karine Jean-Pierre.