Article published on the 2008-06-19 Latest update 2008-06-19 09:03 TU
"The operation started overnight. The situation is normal and there has been no trouble," a police spokesperson in Maysan province Colonel Mahdi al-Asadi said.
This move by Iraqi Prime Minister Nuri al-Maliki is similiar to his March ultimatum against cleric Moqtada al-Sadr's Shia-based militia. That crackdown sparked intense fighting that killed hundreds before the ceasefire last month.
Sadr's supporters claim they are being targeted because they are the principal rivals of Maliki and other pro-government support for Shia support.
On Wednesday Maliki ordered the security forces to refrain from random arrrests of Sadr supporters.
The south is the largest source of the country's oil output and officials say that the crackdown aims to end smuggling of crude to fund militias.
US commanders claim that Maysan is a centre for arms smuggling from Iran, although Tehran denies arming rebels in Iraq.