Iraq's radical Shiite cleric Moqtada al-Sadr on Tuesday threatened a countrywide campaign of civil revolt as security forces battled his militiamen in the southern city of Basra.
Fighting raged from early morning in areas of Basra controlled by Sadr's Mahdi Army militia as troops and police launched a major crackdown on armed groups in the oil hub, considered the nerve centre of Iraq's national economy.
At least seven people were killed and 48 wounded, among them dozens of members of the Iraqi security forces, according to police and medical officials.
Fighting also erupted in Baghdad when Mahdi militiamen attacked offices of the rival Badr militia, while in the west of the capital hundreds of Sadr supporters took to the streets to protest the arrests of Mahdi Army members.
An AFP correspondent said fighting in Basra died away late afternoon and the streets were empty even of security force vehicles.
Sadr, in a statement read by his representative Hazam al-Aaraji in the holy city of Najaf, warned he would launch protests and a nationwide strike if attacks against members of his movement and "poor people" are not halted.
"We demand that religious and political leaders intervene to stop the attacks on poor people. We call on all Iraqis to launch protests across all the provinces. If the government does not respect these demands, the second step will be general civil disobedience in Baghdad and the Iraqi provinces."
The cleric in August ordered his militia to observe a ceasefire following bloody fighting in the shrine city of Karbala blamed on his fighters, which were involved in two rebellions against US forces in 2004.
While Iraqi and US officials say most members of the militia have heeded the order, a number of what the US military terms "rogue elements" continue to attack American forces with mortars, rockets and roadside bombs.
Despite the ceasefire, Mahdi Army members are being subject to raids by the "occupiers" and Iraqi forces which are "destroying Iraqi houses," Sadr's statement said.
"Iraqis in general and Mahdi members in particular are paying the price."
British military officials said Prime Minister Nuri al-Maliki was in Basra to personally oversee the major security force sweep in Iraq's second largest city, but that British troops were not taking part.
Television pictures showed Iraqi troops running through the streets firing weapons and taking cover as ambulances raced past. Thick palls of smoke were seen rising above the city skyline.
The operation against the militias dubbed Saulat al-Fursan (Charge of the Knights) came after a 10:00 pm to 6:00 am curfew was slapped on the entire Basra province on Monday.
After touring Basra on Monday, Maliki vowed his government would restore order, saying the city was experiencing a "brutal campaign" by internal and external groups targeting "innocent men and women."
"This is accompanied by the smuggling of oil, weapons and drugs... Basra has become a city where civilians cannot even secure their lives and property," Maliki said in a statement.