A conference of Afghan groups that begins Tuesday in Germany will try to agree on a post-Taleban administration for Afghanistan.

U.N. officials say privately that the collapse of the Taleban in most of Afghanistan means such an agreement is urgent, if anarchy is to be avoided in the days ahead.

There are four groups attending the conference.

There is a large group representing Afghanistan's former king, Mohammad Zaher Shah, who has been in exile in Rome for the past 28 years, but who is seen as a potential unifying figure. There is a small group representing exiled ethnic-Pashtun tribal chiefs, and there is another small group representing exiled Afghan intellectuals.

But the main force at the conference is likely to be the Northern Alliance, which controls Kabul and much of the rest of the country and enjoys a military advantage over everybody else at the meeting.

Although the nominal head of the Northern Alliance, former Afghan president Burhanuddin Rabbani, has played down hopes the meeting can quickly produce a new transitional administration, the United States and the European Union are putting pressure on the delegates to come up with an agreement.

Washington and Brussels are saying there will be no aid for Afghan reconstruction unless the delegates agree on a broad-based government that includes ethnic Pashtuns in addition to the ethnic Tajiks and Uzbeks who dominate the Northern Alliance.

On the agenda are such questions as how big should a transitional administration be? Who should head it? How long should it be in place before it calls a national council of tribal chiefs to determine a more permanent arrangement?

U.N. spokesman Ahmad Fawzi says the factions at the meeting are representative enough of Afghanistan's political diversity to deal with such questions and begin shaping the country's future. "Afghanistan is a very big country," he said. "And it is a very big fractured country at the moment. We are very lucky that we got four groups together. This is the best we could do at this stage, and it is only the first step along a very long road to achieving the ultimate goal of a fully representative, broadly-based multi-ethnic government."

The United Nations is also proposing a multi-national force under a Security Council mandate as the best option to ensure stability in Afghanistan. But it is not, as yet, offering any details on who would make up such a force. It says it wants the delegates at the conference to give their approval to the idea before submitting it to the Security Council.