Candidates considered loyal to Iran's hard-line Islamic conservatives took at least 149 places in the 290-seat parliament, which has been controlled by pro-reform lawmakers since their landslide win four years ago.
Reformers and self-described independents had taken about 65 seats, according to Interior Ministry figures, the Associated Press reported. The final count is expected Tuesday.
The nationwide turnout in Friday's poll stood at slightly more than 50 percent. In the capital, Tehran, just 33 percent of voters went to the polls, the Interior Ministry said -- a distinct drop from the 67.2 percent in the last parliament elections in 2000.
The parliamentary poll was thrown into turmoil after the hard-line Guardian Council, composed of six clerics and six lawyers, disqualified nearly 2,500 reformers from participating in the election.
Pro-reform politicians urged Iranians to boycott the ballot, attempting to bypass state controlled media by reportedly using e-mail, Web sites and cellular phone text messaging to spread news of their protest.
Despite the lower voter turnout, Iran's supreme leader Ayatollah Ali Khamenei, the country's top authority in all state matters, welcomed the poll showing as a "national and an Islamic epic in the true meaning."
"Those who lost the elections were America, Zionism and the enemies of the Iranian nation," he said on state television, calling the poll "completely credible," according to the BBC.
Outgoing reformist deputies must step down at the end of May, leaving moderate President Mohammad Khatami and his Cabinet the only reformers still in office.
"I am announcing my protest at the illegal and irreligious process of unelected institutions in recent years which reached its peak in the Feb. 20 election," said Fatemeh Haqiqatjou, an outgoing female member of parliament.
About 130 reformist lawmakers resigned earlier this month to protest the mass disqualification of liberal candidates.
Some election-related protests erupted into reported incidents of violence over the weekend, leaving at least eight people dead.
Angry voters attacked state offices in the southern province of Kohkilouye and damaged vehicles, the official IRNA news agency said. Eight people were killed and 30 injured in two other southern provinces in protests over the weekend, according to wire reports.
"This is a very serious crisis that Iran actually faces because what has happened in this month is that the essential legitimacy of the Islamic Republic has evaporated. It is no longer an Islamic republic, it is an Islamic regime," analyst Ray Takeyh, director of studies at the Near East and South Asia Center at National Defense University in Washington, told the NewsHour Friday.
"[O]ne of the lessons that we can draw from this election is that the Iranian people, the vast majority of the Iranian people have become disillusioned with the reformist movement and the reformists in general," Mahmood Monshipouri, chairman of the Political Science Department at Quinnipiac University, also told the program Friday.
American and European government representatives also voiced concerns about the poll's legitimacy at a time when Iran is undergoing close international scrutiny over its alleged nuclear weapons program and a stalled European Union trade pace.
"Candidates have been barred from participating in the elections in an attempt to limit the choice of the Iranian people," U.S. State Department spokesman Adam Ereli told reporters Friday. "These actions do not represent free and fair elections and are not consistent with international norms."
EU foreign ministers criticized the election as undemocratic and warned that it could hamper new efforts to improve relations between Tehran and the West.
"It's plain for everybody to see that these were from the start flawed elections," British Foreign Secretary Jack Straw said Monday as he arrived in Brussels for a meeting with his EU counterparts.
The EU ministers approved a statement expressing "deep regret and disappointment" at the exclusion of reformist candidates and called on Iran to "return to the path of reform and democratization."