There were no bombings at any polling stations — a first since the U.S. invaded Iraq in 2003. Al-Abadi called it a "historic day, spent peacefully by all Iraqis." Riyadh al-Badran, a member on Iraq's national elections commission, said turnout was 44 percent. No election since 2003 saw turnout below 60 percent. More than ten million Iraqis voted.
With no clear front-runner, it could take months for a new Parliament to form a government name a prime minister seen as suitable to the country's rival Shiite political currents, who have adopted diverging positions on Iran.
The low turnout could open the door to Sunni-led and Kurdish electoral lists to play an outsized role in the negotiations, as well. Iraq's population is predominantly Shiite. Results are expected within 48 hours according to the electoral commission.
Despite presiding over Iraq's war on the Islamic State group, al-Abadi was opposed by other Shiite leaders who eclipsed him in charisma and popularity. In his first term, Al-Abadi courted both U.S. and Iranian support in the war on IS.
His chief rivals were former Prime Minister Nouri al-Maliki and Hadi al-Amiri, who heads the powerful, Iran-backed Badr Organization militia, which participated in the war on IS. Al-Abadi was also opposed by the influential cleric Muqtada al-Sadr, a staunch nationalist who has railed against U.S. and Iranian influence in Iraqi politics.
Iraq is beset by chronic corruption, a sputtering economy, and failing public services. "The candidates have not done anything for the people," said Ramadan Mohsen, 50, who said he cast a blank vote in Baghdad's distressed Sadr City slums.
Millions of others decided to abstain altogether. "I am certain these elections are a failure," said Abdelghani Awni, who was at a central Baghdad polling station as an observer. He did not vote. "Forget about change, from the perspective of the economy, of services - forget about it."
Iraq's most senior Shiite cleric spoke out on the issue of voter participation Saturday afternoon, encouraging Iraqis to vote "to prevent the arrival of a corrupt parliament." "The lack of participation will give the opportunity for others to reach parliament and they will be very far from the aspirations of the people," said Sheikh Abdul-Mahdi al-Karbalai, the representative of Grand Ayatollah Ali al-Sistani, on local Iraqi television from Karbala. Sistani has encouraged Iraqis to vote into power Saturday a new political class to combat corruption.
For those who did attempt to vote, some in Baghdad complained of voting irregularities at polling stations linked to a new electronic voting system implemented for the first time this year in an effort to reduce fraud.
Former Prime Minister al-Maliki said he was aware of "violations" at some polling stations in Iraq and complained the process lacked proper oversight. "We are not reassured," al-Maliki told the Associated Press in a phone interview.
Thamer Aref, 45, along with his wife and daughter were turned away from a polling station north of central Baghdad. Aref had turned in his old voter ID card months ago for the biometric identification card required by the new system. However, Aref's biometric card wasn't ready ahead of Saturday and, with neither card, the polling station did not allow him to a cast a ballot.
"I lost my right to vote," he said. Associated Press journalists documented several similar cases at a number of different polling stations across Baghdad Saturday morning. Amira Muhammed, the supervisor of a polling station in Azamiyah, Baghdad, said some people couldn't vote because they did not pick up their new biometric ID cards in time.
"The problem is not with us," she said. A member of Iraq's electoral commission deflected blame for Saturday's reported irregularities. "There were some problems with the electronic equipment due to misuse by some employees," Hazem al-Ridini told the AP.
In central Baghdad, voters supporting al-Abadi said they are doing so because they give him credit for Iraq's military victory over IS. Al-Abadi "took revenge" for civilians killed in insurgent attacks in Iraq "with the victory over Daesh," said 71-year-old Felihah Hassan, using the Arabic acronym for IS.
After IS overran nearly a third of Iraq in the summer of 2014, the group launched waves of suicide bombings targeting civilians in Baghdad and other pockets of government-controlled territory. With support from the U.S.-led coalition and Iran, al-Abadi oversaw a grueling war against the extremists and declared victory over the group in December.
Despite al-Abadi's military achievements, Iraq continues to struggle with an economic downturn sparked in part by a drop in global oil prices, entrenched corruption and years of political gridlock. In addition to al-Maliki, al-Abadi's most powerful competition is from an alliance of candidates with close ties to the country's powerful, mostly Shiite paramilitary forces, and an alliance led by influential Shiite cleric Muqtada al-Sadr.
Jassim Mohsen, 58, who fought against IS with the paramilitary forces, said he was casting his vote for al-Amiri's list, citing the sacrifices of the country's predominantly Shiite militias in the war on IS.
"I elected the Fatah list because they are the only ones who fought Daesh and gave blood," he said. Some Sunnis voting Saturday said they are hopeful this election will help Iraq move beyond sectarian politics and become more inclusive.
Marginalization of Iraq's Sunnis under al-Maliki is seen as a factor that allowed IS to rise in power in Iraq. Al-Abadi has led a more cross-sectarian government marked by his ability to balance the interests of his two allies often at odds: the U.S. and Iran.
The war left more than 2 million Iraqis, mostly Sunnis, displaced from their homes, with cities, towns and villages suffering heavy destruction. Repairing infrastructure across Anbar and Nineveh provinces, both majority Sunni areas, will cost tens of billions of dollars.
Abdulrazaq Kubi and his wife Suheila Mahdi, both Sunnis from Baghdad, said they would not be voting for al-Abadi, casting their votes instead for a Sunni-led political alliance. "The victory is not 100 percent, there is still Daesh here," said Mahdi. The government "is neglecting the refugees because they are Sunni. They left them in the camps, in the winter it floods, in the summers, they go hungry," she added.
There were 329 parliament seats at stake, with nearly 7,000 candidates from dozens of political alliances. Iraq's constitution allows lawmakers more than three months after the ratification of the election results to form a government. But many expect the process to drag on for much longer if there is no clear winner, as dozens of political parties attempt to cobble together a political bloc large enough to hold a majority of seats in parliament.
Associated Press writers Balint Szlanko and Salar Salim in Mosul, Iraq, contributed to this report.