The governor of Iraq's southern province of Muthanna said foreign troops began their withdrawal on Thursday, days after Prime Minister Nuri al-Maliki announced a handover of security in the region.
"The withdrawal of the Multi-National Forces from Muthanna province starts today. It will take more than a month to complete this withdrawal," Governor Mohammed al-Hasani told a news conference in the provincial capital Samawa.
A British military spokesman in Basra said the withdrawal process had already been under way for some time and would take around six weeks.
British Defense Minister Des Browne said this week British forces, who have about 7,000 troops in Iraq, will still monitor security although Iraqis will have overall responsibility.
"It is not decided where the troops will be based but we will keep a responsible overwatch," Browne told Reuters.
The relatively calm province of Muthanna will be the first outside the peaceful Kurdish region to be handed over to full Iraqi control since the U.S.-led invasion in 2003.
Japan has said it will withdraw some 500 troops based in Samawa. Their engineering and reconstruction mission has been controversial at home. Australia also has troops in Samawa.