WASHINGTON (Reuters) - The United States blacklisted five Iranian officials on Thursday, accusing them of preventing free and fair elections a day before a parliamentary vote that it branded a “sham.”

Iran’s election campaign ended on Thursday, ahead of the vote seen as a popularity test for the clerical establishment at a time when relations with Washington are at their worst since the 1979 Islamic revolution.

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

“Many of them were Iranians who questioned the Supreme Leader’s policies,” U.S. Secretary of State Mike Pompeo said in a statement, referring to those rejected from running. “This process is a sham. It is not free or fair,” he said.

The Guardian Council, which must approve candidates, has rejected around 6,850 moderate or conservative hopefuls in favor of hardliners from among the 14,000 applicants seeking to contest the Feb. 21 vote. About a third of lawmakers have also been barred from standing again.

Washington’s action on Thursday 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 members of the Elections Supervisory Committee.

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

Supreme Leader Ayatollah Ali Khamenei has said voting is “a religious duty” but some prominent pro-reform politicians in Iran and activists abroad have called for a boycott.

“The Trump Administration will not tolerate the manipulation of elections to favor the regime’s malign agenda,” Treasury Secretary Steven Mnuchin said in the statement.

Tensions between Washington and Tehran have spiked since Trump unilaterally withdrew in 2018 from the Iran nuclear deal struck by his predecessor, Barack Obama, and began reimposing sanctions that had been eased under the accord.

The vote to pick 290 lawmakers will have no major influence on foreign affairs or Iran’s nuclear policy, which is determined by Khamenei, whose hardline loyalists are likely to dominate the parliament.

Hook, when asked if the new parliament might have an effect on Iran’s diplomacy with the United States, said: “I doubt it, because the day after the elections, the supreme leader is still going to be in charge.”