Iran's parliamentary runoff elections got underway Friday, state media reported, a key vote that is expected to decide exactly how much power moderate forces backing President Hassan Rouhani will have in the next legislature. The balloting is for the remaining 68 positions in the 290-seat chamber that were not decided in the February's voting, in which Rouhani's allies won an initial majority. Iran's next parliament will set the legislative course for the Islamic Republic following last year's landmark nuclear deal with world powers. And though the parliamentary vote isn't expected to herald large-scale change in Iranian policies, it may strengthen Rouhani's hand and make it easier for him to deliver in areas such as promoting social freedoms and reforming the economy. In February, a bloc of reformists and moderate allies of Rouhani won an initial majority, 106 seats, in a vote that saw a 62-percent turnout. The bloc needs to win 40 seats Friday to ensure its control over the parliament, which begins work in late May. But hard-liners, who have in the past controlled the chamber and who only won 64 seats in February, are also hoping to boost their presence in the next parliament. The political affiliation of the other 52 winners in February's election, among them five members of Iran's religious minorities, remains unclear. That makes the runoff so important to cement the control of reformists and moderate conservatives. Polls opened at 8 a.m. Friday and nearly 17 million Iranians are eligible to vote in 55 constituencies, including cities and towns across the nation. In Tehran, Iran's capital and major political powerhouse, moderates won all 30 seats there outright in the first round of voting.Rouhani's moderate and centrist allies made major gains in Feb. 26 elections to parliament and a clerical body that will elect the next Supreme Leader. Butt failed to win a majority of the 290-member assembly. The current parliament is dominated by hardline allies of Supreme Leader Ayatollah Ali Khamenei. "People will vote for 68 undecided seats in constituencies that candidates failed to get 25 percent of votes cast in the first round of the election," said Interior Minister Abdolreza Rahmani Fazli, state TV reported. In a major blow to their hardline rivals, moderates won all 30 seats representing the capital city of Tehran in the first round of elections. Rahmani Fazli said the results will be announced by Sunday. Over the past days, Iranian leaders have urged people to vote. "The importance of the runoff elections is not less than the first round; there is a need for all to participate. Participation in the elections is decisive," Khamenei, who has final say on all state matters, said Wednesday.The election is viewed by many as a referendum on Rouhani's administration, which negotiated the deal with world powers, including the U.S., to limit Iran's nuclear program in exchange for the lifting of international sanctions. While the deal has taken effect, many feel they haven't seen its benefits as Iran's economy remains anemic. Also in February, voters picked members for an 88-seat body of clerics officially charged with selecting the replacement for the supreme leader from high-ranking clerics, including its members. The Assembly of Experts is elected every eight years and there is a chance its members may need to find a successor for the ayatollah, who is 76 years old and underwent prostate surgery in 2014, renewing speculation about his health.Although moderates are expected to gain more seats, the fragility of Iran's economy has forced Rouhani and Khamenei into an uneasy alliance at least for the time being since they may have sharply ideological differences. In the past, the two powerful figures had offered contrasting visions for the Iranian economy with the conservative Khamenei calling for self-reliance and the pragmatist Rouhani urging cooperation with the world. But now, after having achieved a nuclear deal with the West, both leaders have a vested interest in setting aside their differences to secure their political futures and turn the economy round. "Rouhani's political career depends on this issue. If he fails to improve the economy, he will lose the leader's support and will turn into a lame-duck president," said a reformist former official, who is close to Rouhani. "His failure in the economic field, will lead to his political failure."While allaying the fears of Iranian hard-liners against any detente with the West, Khamenei cautiously backed Rouhani's efforts to reach a nuclear deal with the United States and other major powers in 2015, aimed at curbing Iran's nuclear program in return for lifting crippling sanctions. Rouhani will be protected by Khamenei against his hard-line critics so long as he is taking steps to improve the economy a senior official said, on condition of anonymity. But Khamenei's patience is being strained because of a lack of tangible economic benefits since sanctions were lifted in January. Some U.S. restrictions on Tehran remain in place. "For the leader Khamenei, the most important issue is to safeguard the interests of the nation and the country. That is why he backed the president's nuclear policy," said an Iranian diplomat close to Khamenei's office. Some point out that Khamenei's protection of Rouhani will stretch only as far as there is an economic dividend. "But now, the question is what was the use of reaching a deal if it cannot improve people's lives," the diplomat said. Khamenei's core support comes from lower-income people, who have socially, politically and economically invested in the Islamic Republic, analysts say, but this group has yet to benefit from the easing of sanctions. "Hard-liners are concerned that they might even lose the backing of their core supporters who were against any rapprochement with the West but remained silent because of Khamenei's support of the deal," political analyst Hamid Farahvashian said. Rouhani is in a constant power struggle with the country's influential hard-liners and has even faced accusations of undermining pillars of the 1979 Islamic revolution, including "hostility towards the United States." This makes the alliance with Khamenei and his protection more valuable than ever to Rouhani's survival.