BAGHDAD - A fiery protest marked the start on Friday of US Vice President Joe Biden's visit to Iraq, with supporters of the Shiite anti-American cleric Moqtada al-Sadr burning the Stars and Stripes.

Biden met General Ray Odierno, the top US officer in Iraq, and Christopher Hill, Washington's ambassador in Baghdad, who briefed him on the military and political situation, three days after a major US troop pullback.

The vice president's trip, aimed at bridging Iraq's sectarian divide ahead of a complete American military pullout in 2011, comes just after President Barack Obama tasked Biden with overseeing the US departure.

A stark reminder of the legacy inherited by Obama's administration, however, came in Sadr City, where hundreds of supporters of Sadr, who is in self-imposed exile, chanted anti-US slogans.

"No, no America, no, no occupation. Yes, yes Iraq," they shouted as an American flag was reduced to ashes in the sprawling Baghdad Shiite district.

The White House said Biden, who landed late on Thursday, would visit American troops, now stationed on the outskirts of Iraqi cities following their June 30 withdrawal from urban centres.

It also said talks with political leaders, including Prime Minister Nuri al-Maliki, will renew the US commitment to complete the terms of a security deal signed between the two governments last November that set a timeline for the US military exit.

It is Biden's first trip to Iraq since he was sworn in as vice president in January, but he previously made several trips when he was chairman of the Senate foreign relations committee.

The White House said Biden would work closely with Odierno and Hill, as US forces prepare to leave the country for good, ending a military engagement that started with the 2003 invasion ordered by Obama's predecessor, George W. Bush.

"The vice president has been asked by the president to oversee the policy," White House spokesman Robert Gibbs said on the day of the US troop pullback.

Biden would work with Iraqis "toward overcoming their political differences and achieving the type of reconciliation that we all understand has yet to fully take place but needs to take place," he said.

But Gibbs said an idea once put forward by Biden -- dividing Iraq's Shiite, Sunni and Kurdish communities into a federation of autonomous zones -- was not on the table for the Obama administration.

The vice president's arrival in Baghdad was welcomed by Wathad Shaqir, chief of the Iraqi parliament's national reconciliation committee.

"I believe he has brought some suggestions regarding the reconciliation project," Shaqir told state television, noting he was happy that Biden's communal federation idea had been abandoned.

"We are looking forward to a new page," he added.

A key problem facing the reconciliation effort is a Sunni demand that Baathists loyal to now executed dictator Saddam Hussein, who were excluded from politics after the US-led invasion six years ago, be reintegrated.

Major difficulties are also posed by the crucial oil-hub city of Kirkuk, which Iraq's autonomous Kurdish region has laid claim to in a new draft constitution that has irked the central government in Baghdad.

The Kurds have long striven to expand their northern territory beyond its current three provinces to other areas where the population was historically Kurdish.

Kurdistan, whose capital is Arbil in northern Iraq, has its own flag which is raised beside the federal flag, and also has its own slogan, national anthem and national day.

Iraq marked Tuesday's American pullback with a national holiday. The country's 500,000 police and 250,000 soldiers are now in charge in cities, towns and villages. Most of the 133,000 US troops, now based outside of cities, will largely play a training and support role.

Under the Status of Forces Agreement signed in November, US commanders must now seek Iraqi permission to conduct operations, but their troops retain a unilateral right to "legitimate self-defence.