At least 15 killed in protests to support Iraqi Shiite cleric Muqtada al-Sadr

At least 15 people have been killed in Iraq after protesters stormed the country's government palace following the resignation of an influential Iraqi Shiite cleric.

Hundreds of protesters mobbed the building in Baghdad, sparking violent clashes with security forces after Muqtada al-Sadr announced he is quitting Iraqi politics and ordered the closure of his party offices, Sky News reports.

Several demonstrators were wounded by gunfire and a dozen more were injured by tear gas and physical altercations with riot police, medical officials said.

In response to the unrest, a nationwide curfew was announced at 7 pm and the caretaker premier suspended cabinet sessions.

The military called on the cleric's supporters to withdraw immediately from the heavily fortified government zone "to prevent clashes or the spilling of Iraqi blood", according to a statement.

Iraq's government has been deadlocked since Mr al-Sadr's party won the largest share of seats in parliamentary elections in October, but not enough to secure a majority government.

As a result, the country was catapulted into political uncertainty with Mr al-Sadr's refusing to negotiate with his Iran-backed Shiite rivals and exiting from talks.