More than 550 British troops in Iraq have pulled out of their base in Basra, the second largest city in size and importance in the Iraq war. It will be the first time that the base, a former palace of Saddam Hussein, will be without a multinational force since Hussein was ousted from power in 2003.

The palace, which has been the target of daily rocket and mortar fire, will now be controlled by Iraqi forces. However, the British Ministry of Defense said British troops would continue with security for a section of the Basra area until the full exchange of power to the Iraqi government there is completed, a move expected to occur later this year.

As British troops departed from Basra, several Iraqis cheered, calling them “strangers” and “colonists.”

Since the beginning of this year, British troops have handed over to Iraqi authorities control of three provinces in the southern part of the country.

The latest move signals a significant change in British support for the war and in British policy under new Prime Minister Gordon Brown. Mr. Brown has been criticized for Britain’s failure in Iraq and encouraged by those in the United Kingdom to withdraw British forces.

The decision to remove the troops also came shortly before U.S. President George W. Bush and his top advisers made a surprise visit to Iraq to speak with General David Petraeus, who is expected to give a much-awaited assessment of the situation in Iraq next week.

Although the move has strained relations between the United States and Britain, U.S. officials have expressed willingness to resume control of the area if order is not maintained.