WASHINGTON/ISLAMABAD (REUTERS) ? The United States asked NATO Wednesday for unlimited access to allied airspace, as Secretary of Defense Donald Rumsfeld flew to the Middle East to explain American intentions ahead of an expected strike on Afghanistan.

The frayed state of nerves around the world following the Sept. 11 attacks on the World Trade Center and the Pentagon with hijacked aircraft was demonstrated by a false alarm “hijack” in India and an attack on a Greyhound bus in Tennessee by an apparently deranged passenger.

The United States asked its NATO allies for permission to fly through their airspace as well as for the use of air bases in Europe and NATO fuel pipelines.

NATO sources said it was the first time the United States had asked to use the alliance’s Cold War-era network of aviation fuel pipelines since the 1991 Gulf War.

In another military move, the U.S. Army put 1,000 troops from the 10th Mountain Division in New York state on alert for possible movement to Central Asia to join a buildup of U.S. forces near Afghanistan.

A defense official said the troops were under “deployment order,” but no movement had begun. The official denied a Washington Post report that the soldiers had gone to the former Soviet republics of Uzbekistan and Tajikistan to provide support for other U.S. forces.

The United States has built up military forces around Afghanistan in a hunt for the prime suspect in the attacks, Saudi-born militant Osama bin Laden.

A host of factors, including politicians’ travel plans, the humanitarian situation in Afghanistan, public opinion, the weather and Muslim holidays, all point to a short window of opportunity for action between Oct. 8 and mid-November.

“Clearly things can’t wait very much longer. They have a few short weeks. It may be a question of days rather than weeks,” a Western defense attaché said.

Bush’s final decision will depend on whether Washington has vital intelligence about the whereabouts of bin Laden and the location of his al Qaeda organization’s bases.

Defense Secretary Donald Rumsfeld said he had an inkling of bin Laden’s whereabouts, but not an exact location. He also said conventional weapons would not be the determining factor in the war on terrorism.

“It’s going to be a scrap of information from some person in some country, that has been repressed by a dictatorial regime, that’s been sponsoring a terrorist organization, that’s going to provide the kind of information that’s going to enable us to pull this network up by its roots,” the secretary said.