British troops have turned over the civilian airport in Basra, Iraq's second-largest city, to Iraqi control.

The civilian airport will now operate commercial flights.

But the adjacent military airport will be not be handed over to the Iraqi authorities. Instead US forces will take over.

Major General Andy Salmon, General Commanding Officer of British troops in Iraq, spoke at the handover ceremony:

"Having handed over the facility here, the Americans will clearly take over the running of the military airbase so you can expect to see that happening, but the spirit of partnership and support to the Iraqi people and Iraqi security forces and the provincial council and so on will not change."

Britain says it will withdraw its approximately 4,000 soldiers based in Iraq by the end of May.

Mohamed Musabah al Waeli, the governor of Basra, said the handover day is significant:

"On this day we have realised a significant achievement for the Iraqi government in cooperation with coalition forces and the ministry of transport to receive Basra control tower and the Basra International airport facility."

The transfer of the civilian airport was one of British Prime Minister Gordon Brown's remaining key tasks in southern Iraq.

It followed the signing of a Memorandum of Understanding by British military commanders and Iraqi transport officials in Baghdad.

Meanwhile, the US formally transferred control of Baghdad's Green Zone to Iraqi authorities on New Year's Day, and also handed back Saddam Hussein's former palace.

Iraq's prime minister said he will propose making January 1 a holiday marking the restoration of sovereignty.