The attack comes as Iraq is gripped by anti-government protests. More than 240 people have been killed this month as security forces crackdown on the growing protest movement.

The protests have been gaining momentum with tens of thousands of people gathering in a central square in Baghdad and across much of the country's Shiite-majority central southern provinces.

Security and hospital officials say more than 60 protesters were injured on Wednesday by tear gas canisters fired by security forces at protesters in the vicinity of Tahrir Square, which has emerged as the epicentre of the protests.

The protests are over deteriorating living conditions, unemployment and corruption. Protesters have been joined by supporters of an influential Shiite cleric Muqtada al-Sadr, who has called on the government to resign. They are also joined by university and school students.