The Bush administration has announced it is now ready to open negotiations with allied countries on the future global posture of U.S. military forces.

The coming negotiations could see a dramatic overhaul（檢查）of basing and access arrangements for U.S. forces overseas that have been in place for half a century.

But for the moment, senior Pentagon and State Department officials are declining to offer any details of the future vision the Bush administration intends to take into the talks.

And Defense Secretary Donald Rumsfeld told reporters it could be a lengthy negotiating process. "It very likely will take some period of months to complete those consultations and discussions, to come to some conviction about what we actually believe is in the best interests of all of us, the United States as well as our allies and alliances and friends and then it will take some period of years to actually roll out those decisions."

General Richard Myers, the chairman of the military's Joint Chiefs of Staff, acknowledges the prospect of change could make some people nervous.

But he said the goal will be enhancing global security. "However we come out of here, however we rearrange, in the end that we are stronger in terms of our security posture and the posture of our friends and allies."

It is thought U.S. bases in Western Europe could be closed down or substantially reduced in size as a result of the coming talks. Some defense officials have suggested it might be more prudent to have military facilities available further to the east, where U.S. forces could react more quickly to crises in the Mideast or Central Asia.

Other defense officials have suggested the emphasis may be placed on opening bases that would have few permanent troops but which could be turned quickly into staging areas for large forces in the event of an emergency.

Senior Pentagon and State Department officials acknowledge the principles that will guide U.S. negotiators in the coming talks will include flexibility to contend with uncertainty, the development of rapid deployment capabilities and expanded allied roles as well as new security partnerships.