Now that the Northern Alliance has wrestled control of much of Afghanistan from the militant Taliban regime, the group has decided to participate with the U.N. in forming a new, power-sharing government.

"The purpose of the meeting would be to bring together a number of leaders representing different parts of Afghanistan, different ethnicities, different tribes, and see if we can get an interim government in place and then stand up a broader government over time," said Secretary of State Colin Powell on Fox News Sunday.

Powell said he was happy the Northern Alliance finally agreed to the talks — and was hopeful the conference would take place in a matter of days, not weeks.

"We've got to get this moving," he said. "The holdup had been the Northern Alliance, and with this announcement today, we should be able to move forward quickly."

A string of successes over the past week has enabled alliance forces that once controlled a small part of northern Afghanistan to command third-thirds of the country, including the capital, Kabul.

The United States has pressured the Northern Alliance to share power with other factions — including Pashtuns in the south — and to let the United Nations oversee the assembly of a new government.

"For us not to go back to the kind of Afghanistan we've seen in the past, we need this broad-based coalition," Powell said.

Powell did not say where the meeting organized by the top U.N. envoy for Afghanistan, Lakhdar Brahimi, would be held.

But Northern Alliance spokesman Haron Amin said on CBS' Face the Nation said Alliance representatives would go to Europe this week for the meeting, and that it may be held in Germany.

The breakthrough came as a result of meetings in the region between Northern Alliance leaders and James Dobbins, the Bush administration's special envoy for Central Asia.

Brahimi has outlined plans for a two-year transitional government backed by a multinational security force.

Amin said it would be important for women to play a significant role in the new government. Under the Taliban regime, women had virtually no rights.

"Everyone in Afghanistan was so badly brutalized by the Taliban that there is no room for the Taliban in Afghanistan," he said. "But certainly, all other groups should join in the future government."

Powell hopes the meeting can lead to the beginning of administrative control of Kabul in advance of a "more comprehensive, broad-based government."

That, in turn, "may well require some military presence on the ground" to ensure the delivery of humanitarian supplies or provide "a level of stability in the towns that are being liberated," he said on ABC's This Week.

Powell also played down the direct role of Afghanistan's exiled king, 86-year-old Mohammad Zahir Shah, in ruling the country.

"It seems to me that his role would continue to be symbolic as opposed to being the executive or the chief executive of the new government," Powell told Fox News.

The secretary of state said he believed suspected terrorist mastermind Usama bin Laden is still in Afghanistan, though on the run from U.S. airstrikes.

"I don't think this fellow is going to be welcome to anywhere," Powell said. "He is an outcast. He is a murderer, he's a terrorist. The whole world recognizes that. And he is on the run, just as the president said he would be. And we will get him."

Powell said bin Laden was running out of places to find refuge in Afghanistan -- and would be hard-pressed for protection elsewhere.

"It's getting harder for him to hide, as more and more territory is removed from Taliban control," Powell said. "His freedom to maneuver has become quite limited. And I don't think there's any country in the region that would be anxious to give him guest privileges if he showed up."

Powell said he didn't think bin Laden had been successful in his goal to obtain nuclear bombs.

"I don't think he has a nuclear weapon," he said. "The material that we've seen in these safehouses certainly suggests that he was interested in one and they were moving in that direction."

On the military front, U.S. B-52s bombed Taliban positions in the hills outside the city of Kunduz, the last Taliban foothold in the north. The Taliban also held positions in their home base of Kandahar in the south.

"This war is not over. It'll continue for a while, until the Taliban power is totally cracked and other tribes in the south start to reassert control," Powell said.

The military campaign will continue until the United States accomplishes its goal of getting bin Laden and destroying his Al Qaeda terrorist network, Powell said.

Once that is done, the United States will go after the network in all of the 50 countries it's located in around the world, Powell said.

"So let's not see this as all suddenly coming to an end. A long-term campaign against terrorism will take years, and we'll stick with it," Powell said.

The Associated Press contributed to this report.