Reports of fierce fighting circulated Tuesday as splinter groups of the Mahdi Army, loyal to Shiite cleric Moqtada Sadr, fought Iraqi army forces following calls for civil disobedience from Sadr officials.

Prime Minister Nouri al-Maliki went to Basra Monday to supervise security operations following the steady redeployment of British forces to Basra International Airport.

The Iraqi government lacked control over much of Basra, Time magazine said Wednesday, as the region fell under the influence of Iraq's major Shiite factions -- the Mahdi Army, cleric Abdul Aziz al-Hakim's Islamic Supreme Council of Iraq's Badr Organization and a third group, the Fadhila movement.

As the Maliki government pledged to control the militia, the Shiite groups fought each other for control of Basra and the outbreak in the city may be the first test of the Iraqi government and national security forces, Time noted.

But Brian Katulis of the Center for American Progress says the violence suggests the Bush administration's surge policy masked an undercurrent of sectarian violence that is now boiling to the surface.