US Vice President Joe Biden said on Wednesday the United States and Iraq are embarking on a new phase in their ties as Washington keeps its promise to pull all of its troops out of the country.

Biden, President Barack Obama's point man on Iraq, was speaking a day after arriving on a surprise eighth visit to Baghdad since he took office, a trip that follows a bloody seven days in which at least 61 Iraqis were killed.

"Our troops... are leaving Iraq and we are embarking on a new path together, a new phase in this relationship... between two sovereign nations," Biden said at the opening of a meeting of the US-Iraq Higher Coordinating Committee.

"That partnership includes a robust security relationship, based on what... you think that relationship should be."

Biden's trip comes ahead of a December 31 deadline for the withdrawal of US troops from Iraq, which at their peak numbered 170,000 in 2007.

Speaking before the committee alongside Iraqi Prime Minister Nuri al-Maliki, Biden said Washington was keeping its promise to pull out all of its soldiers on schedule.

He said the committee would be the centrepiece of US and Iraqi efforts to build their relationship, including on security issues such as training, intelligence and counter-terrorism.

"We kept our promise to withdraw from Iraq's cities in 2009. We kept our promise to end our combat mission in the summer of 2010," said the US vice president.

"And now, we are keeping our promise we made back in 2008 to remove our troops from Iraq by the end of this year, and they will be removed.

"Drawing down our forces is not only in the best interest of Iraq, but it's in the best interest of the United States of America as well, and the best interest of the relationship."

"In one month, our troops will have left Iraq, but our close strategic partnership... will, God willing, continue," Biden said.

In his remarks, Maliki spoke of "a new page" in Iraqi-US relations.

The premier said he looked forward to "a page of cooperation on different levels, and friendship and partnership between the two countries, economically, politically, scientifically, in trade, tourism, and agriculture," and also "continued cooperation in the security field."

Besides Maliki, Biden also met President Jalal Talabani and parliament speaker Osama al-Nujaifi.

"They covered a broad array of issues in these meetings, including this transition to a civilian lead in Iraq for the United States, (and) the security relationship going forward," a senior Obama administration official said.

Talks also covered "regional issues including Syria," "internal security, especially the need to keep the pressure on violent extremist groups," and "outstanding political issues in Iraq including Arab-Kurd relations, hydrocarbons, etc."

Biden was accompanied by officials including US Ambassador James Jeffrey, General Lloyd Austin, the US military's top commander in Iraq, Deputy Energy Secretary Daniel Poneman, and Assistant Secretary of State Jeffrey Feltman.

Obama on October 21 announced 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.

About 13,800 US soldiers are still in the country, and seven US bases remain to be handed over, according to US military spokesman Major General Jeffrey Buchanan.

Obama's predecessor George W. Bush ordered the invasion of Iraq in 2003, arguing its then leader Saddam Hussein was endangering the world with weapons of mass destruction programmes.

Saddam was toppled, and later executed, but such arms were never found.

Despite the troop pullout, ambassador Jeffrey said Sunday US spending would top $6 billion in 2012 in Iraq, which will still host the largest American embassy in the world and a mission of up to 16,000 people.

Biden said the large US civilian presence was needed in order for Washington to meet its obligations to Iraq.

"Our civilian mission in Iraq... is sized to meet the request and the obligations and the promises we've made," the US vice president said.

"We are here for one reason and only one reason: to assist in the development of the capacity of this great nation."

At the end of the committee meeting, the US and Iraq issued a joint statement declaring their commitment to "forging a strong partnership based on mutual interests that will continue to grow for years to come."

"Our two nations are entering a new phase in our relationship.

"We have a historic opportunity to strengthen our ties beyond security and build a multi-faceted relationship through trade, education, culture, law enforcement, environment, energy, and other important areas," it said.