Heavy fighting erupts in Basra

Heavy fighting erupted in Iraq's southern oil hub of Basra on Tuesday, and a military official said a major operation had been launched against armed groups in the city.

Rival factions from Iraq's Shi'ite Muslim majority and criminal gangs have been competing for control of Basra.

A Reuters witness said he could see columns of black smoke and hear the sound of explosions and machinegun fire in Iraq's second city and gateway to the Gulf.