The United States on Friday handed over to Iraqi control the sprawling Victory Base Complex near Baghdad, the main base from which the US-led war in Iraq was commanded, a US military spokesman said.

"The Victory Base Complex (VBC) was officially signed over to the receivership of the Iraqi government this morning. The base is no longer under US control and is now under the full authority of the government of Iraq," said Colonel Barry Johnson, a spokesman for United States Forces - Iraq (USF-I).

"There was no ceremony, just a signing of paperwork akin to the closing of a home sale," Johnson said in a statement emailed to AFP.

Lieutenant Colonel Angela Funaro, a spokeswoman for USF-I, said that US troops had pulled out from VBC in advance and that just five US bases in Iraq now remain to be handed over.

"All US troops departed as of last night," she said. "The air base which adjoined VBC has transferred to the control of the State Department, but has some troops there."

At its peak, VBC housed more than 100,000 people -- some 42,000 military personnel and more than 65,000 contractors, according to the US army's top historian in Iraq.

The complex includes an area known as Camp Victory, a sprawling collection of canals, man-made lakes, palm trees and palaces from which the US war in Iraq was run.

The top US generals in Iraq lived in the 25,000-square-foot (2,300-square-metre), 20-room waterfront Al-Ez palace in the area, which also includes the 450,000-square-foot (41,800-square-metre), 62-room Al-Faw palace, which served as the headquarters for various Iraq-wide military commands.

Al-Faw was also used to host speeches and ceremonies, including one on Thursday that was attended by US Vice President Joe Biden, Iraqi Prime Minister Nuri al-Maliki, President Jalal Talabani, and US ambassador James Jeffrey.

The complex also contains two apparently decrepit, bombed-out villas on a small island, which is accessible only by a drawbridge.

While their exteriors would seem to mark them as unimportant, one houses a secret prison that once held now-executed dictator Saddam Hussein, as well as his also-executed cousin Ali Hassan Majid, known as "Chemical Ali" for his involvement in poison gas attacks.

President Barack Obama announced on October 21 that US troops would leave Iraq by the end of 2011, bringing to a close an almost nine-year war that has left thousands of US soldiers and tens of thousands of Iraqis dead, and cost hundreds of billions of dollars.

As of Friday evening, there were 10,500 US military personnel, including both soldiers and Department of Defence civilians, remaining in Iraq.

That is down from a peak of about 170,000 soldiers in 2007, at the height of a US troop surge ordered to rein in rampant sectarian bloodshed.

Security officials said on Friday that nine people were killed, including four members of anti-Qaeda Sahwa militia forces, and 30 wounded in bomb and gun attacks in Iraq.

Four people, including a Sahwa leader, were killed and seven wounded in two bombings in Taji, north of Baghdad, while three roadside bombs exploded in the disputed north Iraq city of Kirkuk, killing a woman and wounding 15 other people.

A bomb killed a policeman and wounded six other people south of Kirkuk, and gunmen killed three Sahwa members and wounded two others at a checkpoint north of Tikrit.

Violence has declined in Iraq since its peak in 2006 and 2007, but attacks remain common. A total of 187 people were killed in November, according to official figures.

General Lloyd Austin, the top US commander in Iraq, has warned that the security situation is likely to see "turbulence" as American forces depart and groups including Al-Qaeda seek to take advantage of the vacuum.