A wave of attacks in Baghdad on Thursday killed 57 people as Iraq faced a political crisis, with its vice-president accused of running death squads and the premier warning he could break off power-sharing.

The apparently coordinated blasts, which left 176 people wounded, were the first major sign of violence in a crisis that has threatened the country's fragile political truce and heightened sectarian tensions just days after US forces completed their withdrawal from Iraq.

The attacks, the deadliest in more than four months, largely coincided with the morning rush hour, and security forces cordoned off bomb sites, AFP correspondents and officials said.

Iraqi helicopters could be heard hovering overhead at many of the blast sites and emergency response vehicles rushed to the scene of attacks, while tightened security at checkpoints worsened Baghdad's already choking traffic.

The attacks came in the Allawi, Bab al-Muatham and Karrada districts of central Baghdad, the Adhamiyah, Shuala and Shaab neighbourhoods in the north, Jadriyah in the east, Ghazaliyah in the west and Al-Amil and Dura in the south, the officials said.

Health ministry spokesman Ziad Tariq put the toll at 57 dead and 176 wounded in 10 attacks. Baghdad security spokesman Major General Qassim Atta said there had been a dozen attacks.

Thursday's violence was the worst since August 15, when 74 people were killed and more than 200 people wounded in a series of attacks that struck 17 Iraqi cities.

The attacks come with Iraqi politicians at loggerheads over a warrant issued for the arrest of Vice-President Tareq al-Hashemi, with Prime Minister Nuri al-Maliki demanding that Kurdish authorities hand over the Sunni Arab leader, who is holed up in their autonomous region. Hashemi denies the charges.

Maliki has also called for his Sunni deputy Saleh al-Mutlak, who belongs to the same Iraqiya bloc as Hashemi, to be sacked after he described the Shiite-led government as a "dictatorship".

Iraqiya, meanwhile, has boycotted parliament and the cabinet, and Maliki has threatened to replace their ministers in the year-old unity government.

Washington has urged calm, with the crisis coming just days after US troops completed their withdrawal, leaving behind what President Barack Obama had described as a 'sovereign, stable, and self-reliant Iraq'.

At a news conference in Baghdad on Wednesday, Maliki called for Kurdish officials to transfer Hashemi, and insisted: "We gave the Iraqi dictator Saddam Hussein a fair trial, and we will ensure that a fair trial will also be given to Hashemi."

He warned the Iraqiya bloc that he would replace its nine cabinet ministers if they continued to boycott government sessions.

"If we don't succeed in reaching an agreement, we will move towards forming a majority government," in place of the current national unity administration, Maliki said.

Hashemi has denied the terror charges against him after the warrant was issued for his arrest on Monday, and insisted he is willing to stand trial on condition that it be held in the autonomous Kurdish region.

He has added that apparent confessions aired on state television linking him to attacks were 'false' and 'politicised'. His office has complained of 'intentional harassment'.

Maliki and other leaders have called for talks to resolve the crisis, but the premier's spokesman told AFP he would not accept any mediation over the charges against Hashemi.

Violence is down from its peak in Iraq in 2006 and 2007, but attacks remain common. A total of 187 people were killed in violence in November, according to official figures.