In addition to the air strikes against military and terrorist targets in Afghanistan and the humanitarian drops of food supplies, the U.S.-led alliance is believed to be engaged in ground operations in Afghanistan. Officials are not talking about those secret activities, but military analysts expect the work of special forces or commando units to be more effective than air strikes at stopping those responsible for international terrorist attacks.

After the first round of air strikes got underway Sunday, Defense Secretary Donald Rumsfeld briefed reporters about the operation. Mr. Rumsfeld dismissed a question by one reporter who asked for elaboration on the less visible aspects of the military operation. "If we had wanted it to be overt, we would have discussed it," he said.

But the Secretary did not deny that U.S. ground forces are operating in Afghanistan. "I am disinclined to talk about things that are in process," said Donald Rumsfeld. "And if we had significant numbers of U.S. military on the ground, it would have been known by now."

Defense analyst Jack Spencer says the U.S. government has to be secretive about the work of Special Forces commando units because much of their information is coming from sources close to the Taleban and revealing it would jeopardize the individuals and the mission. Mr. Spencer, with the Heritage Foundation in Washington, says commando units are most useful in identifying targets, not only fixed facilities but also human targets, the leaders of the terrorist network Al Qaida and the members of the Taleban forces helping them. "We often hear about this being an unconventional sort of war, and that is what is unconventional about it - it is the targets," he said. "The targets are very different in what we are engaged in now in Afghanistan than what we are used to. We are still going to use the same sort of strategies and objectives as we always have, and we are seeing that unfold right now, where you identify the air-defense mechanisms, you identify the command and control nodes and those sorts of things. And that is what these initial air strikes are going to be going after. But then, in the longer run we have to be able to get to the people, and I am sure we have people on the ground at this moment and probably have been since right after the September 11 strike against the United States - identifying those targets."

Defense policy analyst Michael O'Hanlon says he would be surprised if any air strikes actually hit suspected terrorist leader Osama Bin Laden or Taleban leader Mullah Mohammad Omar. He says the air strikes are intended to weaken the Taliban so it is more vulnerable to battlefield assaults from the Northern Alliance and other anti-Taleban groups.

Mr. O'Hanlon, with the Brookings Institution in Washington, says commando units should have been in place long before the air strikes began. "My own recommendation would have been to get some commando teams in place before air strikes were conducted on the grounds that even if the air strikes cannot be realistically expected to hit anybody of the top leadership in Al Qaida or the Taleban, those leaders will probably at some point want to come out of their hiding places and assess damage and plot next steps," said Mr. O'Hanlon. "So, you want to have commandos in position such that when that moment occurs, when these leaders come out of their holes and look around and try and communicate, you are in a position to move quickly if you happen to detect them at that point."

Mr. O'Hanlon and Mr. Spencer agree it is not likely the U.S.-led alliance will put large numbers of ground forces in Afghanistan. The terrain does not accommodate infantry or tank units, they say. But Mr. O'Hanlon says Special Forces units, totaling a few dozen or at most a few hundred people, could be very effective in Afghanistan. And he dismisses any suggestion that western trained units would have a hard time working in Afghanistan's harsh circumstances.

Jack Spencer agrees. "I would argue they are actually not at a disadvantage at all," he said. "Their equipment and their information make them superior. Yeah, it is going to be cold in the wintertime there, and that is why a lot of these mountainous regions are at peace in the wintertime. They have to wait till the spring to fight. What we are going to find out here is that the United States and the allied forces are well prepared to fight in any sort of circumstances, any kind of conditions, because of their superior equipment, because of their superior communications."

Mr. Spencer says U.S. forces have technical resources that will help them understand and master the terrain just as well as native Afghan fighters who have lived in the mountains all their lives. Moreover, he notes that allied Special Forces have new uniforms with technologically advanced fabrics that can keep the soldiers warm even in the harshest climates.

Michael O'Hanlon says that although Special Forces units are trained to operate with very little armor, equipment or fuel, they do need good information. And he says getting reliable intelligence to those units would be the most difficult aspect of commando operations.