(AFP) - Fierce fighting erupted Tuesday between Iraq's security forces and the Mahdi Army militia of radical cleric Moqtada al-Sadr in southern Basra city, an AFP reporter at the scene said.
The fighting involved mortars and gunfire and erupted soon after the security forces entered the Al-Tamiyah neighbourhood, the bastion of the Mahdi Army, at 5:00 a.m. (0200 GMT), the reporter said.
Clashes later spread to five other neighbourhoods, including Al-Jumhuriyah, Five Miles and Al-Hayania, the Mahdi Army's main stronghold in Basra, 550 kilometres (350 miles) south of Baghdad.
Police confirmed an operation was underway against the Mahdi Army in Basra while the Sadr movement said it was ready to negotiate a ceasefire.
"We began operations at 5:00 a.m. There is fighting between security forces and the Mahdi Army," said police spokesman Major Karim al-Zubaidi.
A British military spokesman said Iraqi Prime Minister Nuri al-Maliki is personally overseeing the operation launched early Tuesday.
"The prime minister came down to Basra from Baghdad yesterday along with a delegation. He is overseeing the operation. He is at an Iraqi military base," Major Tom Holloway told AFP.
"We are awaiting details of the operation as we speak."
Another military official said British troops were not participating in the crackdown. "It is an entire Iraqi operation," she said.
Officials at the main hospital in Basra said a number of wounded people had been brought in but there were no immediate reports of anyone killed.
A spokesman for Sadr's office in Basra, Harith al-Athari, told AFP the Sadrists wanted to end the stand-off.
"The situation is bad and we regret the fighting. We are ready for negotiations and want to calm things," he said.
Liwa Sumaysim, head of Sadr's political bureau in the central city of Najaf, denounced the bloodletting.
"We do not want the situation as it is in Basra. We are against bloodshed, especially in this critical period of time," Sumaysim told AFP.
"The Sadr movement is being targeted in Basra, that is why this tension has been created. The Iraqi government forces should not use force against poor people," he added.
"The Sadr movement has called for an urgent meeting of their leaders to consider all the available choices and we will announce the outcome when we finish the meeting."
The fighting comes a day after a visit to the city by Maliki and an announcement late Monday by General Mohan al-Furayji, the Iraqi commander in charge of security in the south of Iraq, of a security operation throughout Basra province.
Mohan, announcing an immediate and indefinite 10:00 p.m. until 6:00 a.m. curfew in the province, said the security sweep was designed to "impose the law and chase the criminals."
Vehicle access to Basra would be temporarily closed from neighbouring provinces during the evening hours from Wednesday and until Friday, he said, while teaching at schools and universities has been suspended from Tuesday until Thursday.
Basra businessman Mohammed al-Hajaj said troops had flooded the streets of the city on Monday night and that most people were remaining indoors on Tuesday.
"All the Iraqi forces are out in the streets of the city," he said.
"We heard shooting in the night and again this morning."
Hajaj said shops had closed at 10:00 p.m. (1900 GMT) on Monday when the curfew came into effect and the streets had emptied of people and vehicles.
Basra province was handed over to Iraqi control by British forces in mid-December.