For the past several years, the United States has stationed forces in the central Asian countries of Uzbekistan and Kyrgyzstan.
Marshall Goldman, a long time-expert on Russia and the former Soviet Union, says the United States planned to send troops there following the September 11th, 2001, terrorist attacks in New York and Washington.
"After September 11th and the United States' decision to go after the Taleban and Osama bin Laden, who was then in Afghanistan, the United States was looking for places to establish air bases, so that it could supply what became the invasion force in Afghanistan," said Mr. Goldman. "And it made sense to go to the Central Asian region, where these countries were now independent - they had broken away from the Soviet Union when it broke up - and to establish bases there."
The United States received permission to station troops on two sites: in Uzbekistan at the Karshi-Khanabad military base and in Kyrgyzstan, at the international airport in the country's capital, Bishkek.
Defense Department spokesman Lieutenant Commander Joe Carpenter says the forces there bolster operations in Afghanistan.
"With Kyrgyzstan, we have approximately 1,000 personnel that are there in support of the air operations from the Kyrgyzstan Bishkek airport, and in Uzbekistan, it is approximately 800 people that support our operations there," he said.
But the presence of U.S. forces at these two bases is now in jeopardy. A summit earlier this month of the Shanghai Cooperation Organization - bringing together Russia, China, Kazakhstan, Tajikistan, Uzbekistan and Kyrgyzstan - called on the United States to set a timetable for withdrawing those troops. Following the summit, the host nations repeated that call in separate statements.
One of the reasons given for the withdrawal of U.S. military forces is that, in the words of the summit participants, "the active military phase in Afghanistan is over." Defense Department spokesman Carpenter disputes that view.
"With respect to Uzbekistan and Kyrgyzstan, those airfields - the airfield and the airport - those air operations have been critical in helping us combat the Taleban and al-Qaida, facilitate delivery of humanitarian assistance into northern Afghanistan and as a result, help spread democracy to Afghanistan," he said. "But I will remind you that Afghanistan remains a very difficult location. Operations are still ongoing with the coalition, with NATO forces and U.S. forces and those two facilities are still critical to our operations. This is going to be a long-term effort to help Afghanistan build that democratic institution and keep al-Qaida and the Taleban at bay."
Experts believe there are other reasons for the call to withdraw U.S. troops from central Asia.
In the case of Uzbekistan, analysts point to strong western criticism of President Islam Karimov following events in the city of Andijan in May, when hundreds of Uzbek civilians were reported killed by security forces. A recent United Nations report citing eyewitness accounts said what happened in Andijan amounted to a "mass killing." The U.N. also repeated its call for an international inquiry.
"The trigger was Uzbek anger at U.S. criticism of the Uzbek government for the Uzbek government's failure to agree to an independent international inquiry into what happened in Andijan," said Martha Brill Olcott, central Asian expert with the Carnegie Endowment for International Peace. "To say that the U.S. leadership and the Uzbek leadership don't see eye to eye with one another today is an understatement. It's probably the tensest point in U.S.-Uzbek relations any time since the existence of an independent Uzbekistan. I don't know that the Uzbek regime would have wanted the base removed if Andijan had not occurred."
As for Kyrgyzstan, Ms. Olcott believes there is another aspect to consider.
"I don't think the Kyrgyz on their own would have pushed for a statement that called for the withdrawal of a U.S. base," she added. "I think they are under very strong pressure from China and Russia to do so. They really are in a very hard position. Their instincts are to have very close ties with the West, but not to antagonize Russia or China."
Analysts also say what happens to U.S. forces in central Asia will have an impact on the military's strategy globally. Philip Saunders with the National Defense University says the Defense Department's evolving plan is much less dependent on large, permanent overseas bases and more dependent on lighter, shorter-term access agreements with host nations.
"So basically, the United States military is trying to learn to operate in a much more skeletal manner, so that it can deploy around the world as necessary and Central Asia is one area where that concept is being worked out," he said.
Many analysts agree the U.S. can't operate from a country's territory, if that country won't allow it. In the meantime, U.S officials say the United States has agreements with Uzbekistan and Kyrgyzstan concerning the use of those bases, and each side must abide by them.