A key election for a new Iraqi parliament was underway on Wednesday as the country continued to slide deeper into sectarian violence more than two years after U.S. forces left the country.

Polls across the Arab, energy-rich nation opened at 7 a.m. local time and will close at 6 p.m.

It is the first national ballot after the Americans left in 2011, the election is being held amid tight security provided by hundreds of thousands troops and police.

Iraq’s 22 million registered voters are electing a 328—seat parliament.

A Shiite party led by Nouri al—Maliki, Iraq’s prime minister of eight years, is expected to win the most seats but is unlikely to win a majority.

Al—Maliki will have to cobble together a coalition if he is to retain his job for a third, four—year term, a tough task given the harsh criticism he has been under from his one—time Shiite, Sunni Arab and Kurdish allies.

The Shiite al—Maliki rose from relative obscurity to office in 2006, when Iraq’s sectarian bloodletting began to spiral out of control, with Sunni militants and Shiite militias butchering each other’s communities.

Over the years that followed, Sunni tribes backed by the Americans rose up to fight al—Qaida—linked militants, while al—Maliki showed a readiness to rein in Shiite militiamen and by 2008, the violence had eased.

But the Sunni—Shiite violence returned, stoked in part by al—Maliki. His moves last year to crush protests by Sunnis complaining of discrimination under his Shiite—led government sparked a new wave of violence by militants, who took over the city of Fallujah in the western, Sunni—dominated province of Anbar and parts of the provincial capital Ramadi.

Iraqi army and police forces battling them for months have been unable to take most areas back.

At the same time, many Iraqis increasingly complain of government corruption and the failure to rebuild the economy.

The violence has continued right up to the day before the vote. On Tuesday, back—to—back bombs ripped through an outdoor market northeast of Baghdad, the deadliest in separate attacks that officials said killed 24 people.

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