Senior Bush administration officials say it is too soon to say whether the United States will seek to establish permanent military facilities in Iraq as part of its global realignment of forces.

A senior Bush administration official says uncertainties about the situation in Iraq have made it virtually impossible to predict whether the United States will seek permanent military bases there.

Speaking to reporters at the Pentagon on the administration's ongoing review of its global military posture, the official says that what he terms "the end game" in Iraq "is a piece of the puzzle that has not totally been defined."

Although the Pentagon has disclosed plans to trim its forces in South Korea by one-third and is negotiating other troop reductions and movements in both Europe and Asia, the official says that in Iraq, "because there are ongoing operations...we will just have to see how that evolves."

The United States now has close to 140,000 troops in Iraq, more than originally planned more than a year after coalition forces entered the country to topple the regime of Saddam Hussein.

The higher number was sought by commanders in response to stepped up attacks by anti-coalition insurgents. U.S. officials have voiced concern the level of attacks may increase as the planned transfer of sovereignty to an interim Iraqi government draws near.

In the latest such attack, saboteurs in northern Iraq blew up a major oil pipeline, causing power cutbacks.

Iraq's interim prime minister, Iyad Allawi, has said foreign troops will be needed in his country after the U.S.-led occupation formally ends on June 30.

U.S. forces will be staying on. But a senior Pentagon official says Iraqi bases will belong to the Iraqis. The official, speaking on condition of anonymity, also makes clear the United States will maintain a presence in the years to come only if Iraqi authorities ask, as other U.S. allies have asked in years past.

Defense officials are also stressing to reporters that while there are likely to be fewer U.S. troops stationed overseas under the planned global-force realignment, it is a mistake to focus on simple numbers.

They say planners are focused instead on military capabilities and the ability to move forces and equipment promptly in the event of a crisis anywhere.