Defense Secretary Donald Rumsfeld says the war in Afghanistan is far from over, even though the last remaining al-Qaida terrorist fighters now appear bottled up in the country's Tora Bora region and may be willing to surrender.

Pentagon officials say they are not sure if the surrender talks going on between al-Qaida holdouts and Afghan anti-Taleban forces are serious. They warn the negotiations could be a ruse designed to buy time for at least some al-Qaida fighters to escape.

The officials spoke to VOA after Defense Secretary Donald Rumsfeld took an equally cautious approach in remarks to reporters about the apparent success of the two-month-old U.S. military operation in Afghanistan.

Mr. Rumsfeld says despite battlefield advances, the war is entering an extremely dangerous phase. "A wounded animal can be dangerous," he said, "and so, too, the Taleban and al-Qaida can hide in the mountains, they can hide in caves, and indeed they can hide in cities, they can escape across borders and regroup and then plot to strike again as they have promised to do."

The fighting around al-Qaida's last Tora Bora stronghold has been described as fierce. Daunting U.S. AC-130 gunships are hammering away at terrorist positions.

Pentagon officials say parallel to the continuing fighting, U.S., Afghan and Pakistani forces are trying to seal off potential overland escape routes that might be used by both al-Qaida and Taleban forces.

Mr. Rumsfeld says despite the rapidly changing situation, the U.S. goal remains the same. Mr. Rumsfeld said, "[It is] to capture or kill all the al-Qaida and prevent them from escaping into other countries or other locations in Afghanistan where they can continue their terrorist activities. It is to capture or kill the senior Taleban leadership."

Pentagon officials say some al-Qaida leaders may have been killed in Sunday's devastating drop of the largest conventional bomb in the U.S. military arsenal, the massive 6,800 kilogram "daisy cutter", dropped on a Tora Bora region cave.

But these officials say they have no reason to believe al-Qaida leader Osama bin Laden was among the casualties. As one top defense official puts it, "we're not operating on the basis that he is dead."