BAGHDAD (AP) — Early voting has begun for Iraq's security forces, prisoners and hospital patients ahead of Saturday's national parliamentary elections.

The independent body that oversees Iraq's elections says thousands of people are expected to cast their ballots before polls close Thursday evening.

There is no clear front-runner in the upcoming elections, with Prime Minister Haider al-Abadi facing stiff competition from political alliances with closer ties to Iran.

Nearly 7,000 candidates are vying for 329 parliament seats. No single alliance appears capable of winning a majority, so it will likely require months of negotiations to form a new government and choose a prime minister.

The vote will be the first since Iraq declared victory over the Islamic State group and the fourth since the 2003 U.S.-led toppling of Saddam Hussein.