Members of Iraq's security forces were injured on Wednesday in a grenade attack in Baghdad, as political jockeying over the selection of a new prime minister continued.

Baghdad's Operations Command said four of the nine injured troops were in a critical condition after an "unidentified man threw a hand grenade at security forces at a checkpoint near the central bank".

Protests have gripped the capital since early October and Iraq's Central Bank on Rasheed Street has been at the heart of demonstrations.

At least 400 people have been killed and thousands wounded in the capital since the unrest began.

On Tuesday, protesters burnt an Iranian consulate in southern Iraq for a third time.

Five rockets landed inside Ain Al Asad airbase, a sprawling complex in western Anbar that hosts US forces, causing no casualties and little damage, Iraqi security said.

President Barham Salih met Iraq's main political blocs as a 15-day constitutional deadline to name the next prime minister nears, two Iraqi officials said.

Prime Minister Adel Abdul Mahdi announced his resignation on Friday.

The Sairoun bloc, led by influential Shiite cleric Moqtada Al Sadr, wrote to Mr Salih saying it supported protesters' right to support a premier of their choice.

Anti-government protesters in Najaf burned tyres and hurled them towards the main gate of the Iranian consulate.

The building was empty at the time of the attack and there were no casualties, police said.

The incident came after hours of tense standoff with security forces earlier on Tuesday when protesters surrounded a key shrine in Najaf.

Tens of demonstrators gathered around the Hakim shrine, demanding that Mr Al Sadr help them enter and symbolically take control.

Al Sadr commands Saraya Salam, a powerful militia group. A few protesters and some elderly tribal sheikhs were eventually permitted to enter the shrine and inspect it.

Demonstrators demanding reform have flooded the capital and the Shiite-majority south since October, in the largest grassroots movement the country has witnessed in years.

Seen as a threat to the ruling elite, rallies were met with violence from security forces and armed groups, leaving nearly 430 people dead and 20,000 wounded - the vast majority demonstrators.

The United Nations envoy to Iraq called on decision-makers to act fast in response to demands for change.

Posters of protesters who have been killed in demonstrations and their belongings are displayed in Tahrir Square during ongoing anti-government protests in Baghdad. AP Photo University and college students carry pictures of people who were killed at an anti-government protests, in Basra. Reuters Security forces close River Street during ongoing anti-government protests in Baghdad. AP Photo Anti-government protesters gather on barriers set up by security forces to close Rasheed Street during ongoing protests in Baghdad. AP Photo Demonstrators gather at Tahrir Square during ongoing anti-government protests in Baghdad. AP Photo Anti-government protesters gather near barriers set up by security forces to close Rasheed Street during ongoing protests in Baghdad. AP Photo Anti-government protesters and security forces face off on River Street during ongoing protests in Baghdad. AP Photo Anti-government protesters and security forces face-off on River Street during ongoing protests in Baghdad. AP Photo

"Political leaders do not have the luxury of time and must rise to the moment," Jeanine Hennis-Plasschaert said on Tuesday.

Demonstrators have protested rampant corruption, lack of jobs and poor public services.

Despite the oil wealth of Opec's second-biggest producer, one in five Iraqis lives in poverty and youth unemployment stands at one quarter, the World Bank says.