Everything you need to know about Iraq's election

Iraqis are heading to the polls for the fifth time since 2003, after the US-led invasion ended Saddam Hussein's nearly 25 years of rule. 

Here are the key facts that you need to know about today's vote:

• 167 parties and more than 3,200 candidates are competing for 329 seats in Iraq's parliament 
• A new law designed to help independent candidates led to the election being called several months earlier than planned in response to mass anti-government protests two years ago
• Iraqi elections are often followed by months of protracted negotiations over a president, a prime minister and a cabinet
• The biggest Shia Muslim blocs in the election are those of Muqtada al-Sadr and a separate coalition of Iran-aligned parties with paramilitary wings. Kurds have two main parties that rule the autonomous Kurdistan region, and Sunni Muslims this time have two main blocs. Meanwhile, the Yazidi minority has four dedicated seats in parliament