"Once we've completed the reduction of the combat presence, then I think we begin a process of negotiating" with Baghdad, Defense Secretary Leon Panetta told reporters on board a US military aircraft taking him on a regional tour of Asia. Negotiations would aim "to determine what will be the nature of that relationship, what kind of training do they need, what kind of security do they need, how can we provide them in an effective way," Panetta said.

Panetta comments came hours after President Barack Obama announced on Friday that all American soldiers currently based in Iraq would pull out as planned by December 31 and that no smaller force would be left behind.

The defense secretary cited Baghdad's recent purchase of US F-16 fighter jets as an example where military cooperation will be required as Iraqi pilots and mechanics must be trained by Americans.

An agreement signed between Washington and Baghdad had required that all US troops leave Iraq by the end of 2011 but the two countries had been negotiating since August over whether several thousand American trainers would stay longer.

However, Obama said earlier Friday that all 39,000 US troops currently in Iraq would come home as planned, a decision Panetta reiterated while stressing that Washington continues to seek a long-term relationship with Baghdad.

"Today's announcement means that by the end of this year, there will a clear end to the US combat mission in Iraq," Panetta said. "We now turn our full attention to pursuing a long-term strategic partnership with Iraq that's based on mutual interest and mutual respect.

"Our goal will be to establish a normal relationship, similar to others in the region, that focuses on meeting security and training needs," he added.

The United States has several such partnerships with Gulf nations, Panetta said, referring to the presence of 5,000 US soldiers in Bahrain, 3,000 in the United Arab Emirates, 7,500 in Qatar, and about 200 in Saudi Arabia.