TEHRAN, Iran – Iran's supreme leader called on Wednesday for a high turnout in this week's presidential election, urging voters to head to the polls and send a message to the United States -- but stopped short of saying which candidate he prefers of the four remaining in the race.In a televised speech, Supreme Leader Ayatollah Ali Khamenei said the United States and its allies, including the "pathetic prime minister of the Zionist regime," or Israel, are closely watching the vote on Friday.He called the election a "great popular epic," saying that while the region is "drowned in anxiety," Iran is "peacefully and safely holding an election.""From the U.S. state apparatuses to European powers and regional countries aligned with America, to the pathetic prime minister of the Zionist regime, all are closely watching (the vote) and how and in what spirit" the Iranians will cast ballots, Khamenei said.President Hassan Rouhani, a moderate, is seeking re-election in a vote that will largely serve as a referendum on his outreach to the West, which culminated in the 2015 nuclear deal Iran struck with world powers. Under the accord, Iran agreed to limit its enrichment of uranium in exchange for the lifting of some economic sanctions.Despite the nuclear deal, Khamenei --who will remain Iran's top decision-maker -- remains deeply suspicious of the United States and its intentions toward Iran.Khamenei is believed to favor Rouhani's main challenger, the hard-line candidate Ebrahim Raisi, who has support from major clerical bodies, hard-liners in the establishment as well as close allies of former hard-line President Mahmoud Ahmadinejad.Interior Minister Abdolreza Rahmani Fazli said turnout is expected to exceed 70 percent. Some 56.4 million people out of a population of 80 million are eligible to vote.Fazli said the vote counting would commence after midnight and that the results would be announced "sooner" than in previous elections. In past elections, the results have been announced two days later, on Sunday.Also Wednesday, Hassan Qashqavi, deputy foreign minister in charge of consular affairs and Iranian expatriates, said polling would also be held on Friday for Iranians expatriates in 102 countries, including the United States.The largest number of polling stations -- 55 -- would be in the U.S., where more than 1 million Iranians live. In the 2013 election, 20 polling stations opened in America for Iranian expats.According to reports on opposition website Kalemeh.com, Iranian opposition leaders Mir Hossein Mousavi and Mahdi Karroubi, who have been under house arrest since 2011 after they challenged Ahmadinejad's 2009 re-election, each issued a statement supporting Rouhani.In his 2013 campaign, Rouhani vowed to lift the house arrests of Mousavi and Karroubi but that promise remains to be fulfilled. Rouhani won the presidential election that year with nearly 51 percent of the vote. Turnout for that vote was 73 percent.Last week, Iran's official IRNA news agency published the results of a survey in which nearly 64 percent of a 6,047 person sample group said they will be voting, while 20 percent said they were undecided.Historically, the more Iranians who cast ballots, the greater the chance a reformist or a moderate like Rouhani will be elected.Besides Rouhani and his main rival Raisi, two other candidates -- Mostafa Hashemitaba, a pro-reform figure who previously ran for president in 2001, and Mostafa Mirsalim, a former culture minister -- are in the running but are widely expected to drop out of the race before polling starts.