The US bombing campaign in Afghanistan will start to wind down at the end of this week and the Pentagon plans to begin the next phase of the war on terrorism by sending a significant number of additional ground troops to the Middle-East and central Asia, according to defence officials.
The deployment of the additional forces is not a prelude to a full-scale conventional ground attack on Afghanistan, they said, but the next step in what is an ad hoc approach to an unconventional war. Their presence will give planners maximum flexibility as they consider options in the days ahead, a senior defence official said.
"They [THE TROOPS] will start to go but it's not because we have a clear and defined plan," the official said. "We want to position ourself in such a fashion that we have a wide range of options."
The additional troops are a fraction of the number sent to the 1991 Persian Gulf war. They could do everything from bolstering the border defences of Uzbekistan to flying into Afghanistan to temporarily holding an airfield or cordoning off an area that is being searched.
Asked whether the Pentagon was considering large-scale ground attacks inside Afghanistan, one official said: "Nothing has been ruled out."
The movement of ground troops will also be intended to reinforce the message that the US government is determined to carry out a long-term, wide-ranging campaign against terrorism, the senior defence official said.
Some Arab allies had worried about the Americans' tenacity and a major theme of Defence Secretary Mr Donald Rumsfeld's tour of the Middle-East and central Asia last week was that the Us was in it for the long haul.
The build-up will begin with the movement of 1,000 soldiers from the US army's 10th Mountain Division to join the 1,000 already in central Asia. Additional troops will come from posts in the US but some almost certainly will be pulled out of the US peacekeeping missions in Bosnia and Kosovo, those officials added.
Other NATO countries are expected to send replacement troops to keep the Balkans operations fully staffed.
Underscoring the long-term nature of the US campaign against terrorism, commanders of the units sending the troops are being told to expect the mission to last as long as a year, although the individual troops probably will be deployed for three to six months, and then replaced by other members of their unit, said an official familiar with the deployment orders.
But the signal being sent is clearer than information about how the soldiers will be used. The senior defence official said that it was possible they could take part in offensive actions inside Afghanistan. Another official, nearly as well-connected, indicated that the major role played by the new ground troops would be "force protection" - that is missions such as providing perimeter security for the air force units deploying to Uzbekistan.
It is unclear what other units are being sent and where they might wind up in the region around Afghanistan. One army general and another officer said they had been told that elements of the 101st Airborne Division and much of the 160th Special Operations Aviation Regiment, both based at Fort Campbell, Kentucky, had been notified that they should be prepared to deploy overseas by October 16th.
One also said that the 101st division had been notified that it would not be asked to send a battalion to the peacekeeping mission in the Sinai Desert, as had been planned.
A spokesman for the Army Special Operations Command declined to comment on whether the 160th special regiment had received a deployment order. The division's website carries the vague message: "Our thoughts and prayers are with the soldiers of the 101st Airborne Division joining the peacekeeping around the world."
One general said he expected the army would mount an operation somewhere near Afghanistan that resembled Task Force Hawk, the force of attack helicopters, tanks and soldiers that was sent to Albania during the Kosovo war but was never sent into combat.
Army helicopters - most likely from the 160th Special Operations Aviation Regiment, the army's only unit of special operations helicopters - are likely to be placed aboard the USS Kitty Hawk, which recently left Japan without most of its usual complement of aircraft. That aircraft carrier is likely to play a key role in future special forces raids into Afghanistan.
Military planners have taken pains to reduce the US military's "footprint" in Pakistan. So the Kitty Hawk will pick up the army helicopters somewhere in the Persian Gulf region, the official said, and then steam to the Arabian Sea off the coast of Pakistan. The helicopters then will fly to an air base inside Pakistan, where they will be loaded with special Forces troops flown there on C-130 transport aircraft.
From there, the refuelled helicopters will head into Afghanistan, the senior defence official said.