At least 17 people have been killed and dozens injured as gun battles erupted in the Iraqi capital following a suicide car bomb attack on police.
This was some of the heaviest street fighting in months
After the bomber struck, up to 40 masked gunman opened fire with assault rifles and rocket propelled grenades.
Three police officers were among the dead in Baghdad and at least 53 people were injured, police told the BBC.
The violence came as Iraqi security forces remained on high alert as talks on a draft constitution continued.
In other developments:
- Supporters of radical Shia cleric Moqtada Sadr clash with residents and rival Shias in the city of Najaf, after Mr Sadr's followers re-open an office close to the city's Imam Ali shrine.
- Mr Sadr's followers, who oppose the draft Iraqi constitution, join a Sunni demonstration against any deal in the town of Hawija.
- Shia pilgrims returning to Iraq from a visit to the Iranian city of Mashad are attacked by gunmen as they make their way to the city of Baquba.
A crowded area of western Baghdad was sealed off as police battled to contain the worst street fighting in months.
Police said two suspected insurgents were arrested and the body of the car bomber was recovered.
Several police and civilian cars were hit by small arms and rocket fire and set ablaze during the fighting, witnesses said.
Iraq's overworked hospitals were inundated with casualties again
Iraqi police and US soldiers moved to secure the area as gunmen continued firing into the afternoon.
Injured police and civilians were taken to Baghdad's al-Yarmouk hospital.
"All I remember is that I was sitting in my shop and the shattered glass fell on me," one injured man told the Associated Press.
The attack came as Iraqi politicians struggled to reach an agreement over the country divisive draft constitution.
An influential Sunni Arab figure has accused Iraq's Shia-controlled interior ministry of mounting a campaign of arrests to stop Sunni Arabs registering to vote in a referendum on the constitution.
Ahmad Abd al-Ghaffour al-Samarrai, head of the Waqf, the Islamic trust responsible for the upkeep of mosques, said the alleged arrest campaign was under way in the town of Madain, south of Baghdad.
He called on the government to order the release of all those who had been detained.
Iraq's Sunni leaders have threatened to derail the constitution amid disagreements over the role of federalism and power structures within Iraq.