It said the move targeted those "undermining democracy in Liberia, including through manipulation or rigging of the electoral process, use of violence... or engagement in any other activity designed to improperly influence the outcome of an election".

The State Department said the policy reflected a commitment to support Liberians in their desire to have a free and fair vote.

It did not name any specific individuals.

President George Weah is seeking a second term in office.

He'll face opposition leader Joseph Boakai who was the defeated candidate in the last election five years ago.