This was the first British handover of a southern Iraqi province in 2007. In December 2006, the Baghdad government acquired responsibility for Najaf.

In a ceremony on Wednesday, the government was assigned police and military operations in the southern province, some 350 kilometers south of Baghdad, Middle East Newsline reported.

"We should work to create these circumstances in all provinces, in order to revert security to Iraqis and end the foreign presence," Iraqi National Security Adviser Muwafeq Al Rubaie said.

In July 2006, Iraq was assigned the Muthanna province.

The handover took place amid mass-casualty attacks around the Iraqi capital. On Wednesday, at least 200 people were killed in a series of car bombings in Shi'ite neighborhoods around Baghdad. At least one of the bombs was believed to have contained chlorine in an effort to increase casualties.

"We've seen both inspiring progress and too much evidence that we still face many grave challenges," U.S. military spokesman Maj. Gen. William Caldwell said. "We've always said securing Baghdad would not be easy."

So far, four out of Iraq's 18 provinces have been relayed to full government control. Officials said additional provinces would be handed over in 2007.

"Maysan will be followed by the three Kurdistan provinces, a month from now," Prime Minister Nouri Al Maliki said in a message read by Al Rubaie. "After that Kerbala and Wasit. Then, it will be province by province until we achieve this before the end of the year."

British Defence Secretary Des Browne said the 7,000 British troops would remain in southern Iraq and continue to train the Iraqi military and police. Browne said the British Army would be available to respond to any emergency in Maysan.