The United States on Thursday blacklisted five Iranian officials, accusing them of preventing free and fair elections, a day before a parliamentary vote being seen as a referendum on the handling of various political and economic crises.

The Treasury Department said in a statement it imposed sanctions on the officials, members of Iran's Guardian Council and its Elections Supervision Committee, over the council's role in disqualifying several thousand candidates.

Thursday's action targeted Ahmad Jannati, the Secretary of the Guardian Council, Mohammad Yazdi, a member of Iran's Guardian Council who was formerly Iran's first Judiciary Chief, and three additional members of the Elections Supervisory Committee.

The sanctions freeze any US-held assets of the officials and generally bar Americans from doing business with them.