U.N. hopes for speedy action to install a broad-based government in Afghanistan are on hold because the victorious northern alliance doesn't appear to be in any hurry to share power.

In just over a week, alliance forces that controlled a tiny part of northern Afghanistan swept south as Taliban fighters fled to escape punishing U.S. airstrikes. Suddenly, two-thirds of Afghanistan is in alliance hands, including the capital, Kabul, and warlords from the various alliance factions are filling the power vacuum.

"It's all happened quicker than we thought," Britain's U.N. ambassador, Sir Jeremy Greenstock, told British Broadcasting Corp. radio Saturday. "We didn't realize the Taliban were such a house of cards."

Former president Burhanuddin Rabbani, whose faction dominates the alliance toppled by the Taliban in 1996, returned to Kabul on Saturday, appearing to further entrench the alliance's hold on the country.

This wasn't part of the U.S. or the U.N. game plan.

On Saturday, U.N. Secretary-General Kofi Annan strongly reiterated the need for a government that includes a wide range of Afghan parties.

"If they do not do that, and one group tries to control power and assert itself, it is going to be a problem down the line. And I would hope that Mr. Rabbani also is aware of this happening since he knows intimately the history of his own country," Annan said during a visit to Ottawa.

The United States had gotten a promise from the northern alliance not to take Kabul so the United Nations could quickly arrange a meeting of Afghanistan's disparate ethnic groups and put together a broad-based government to run the country.

But with the alliance savoring its newfound power, the prospect of a truly representative government has become more uncertain.

A White House official said Saturday that the United States has been pressuring the northern alliance — largely made up of ethnic minorities — to share power and to let the U.N. oversee assembly of the new government. Several U.S. officials are in the region and in direct contact with the northern alliance, including James Dobbins, the special envoy for Central Asia.

The official, speaking on condition he not be identified, reiterated that the administration does not want to force a government on Afghans. But the new government must represent the country's diverse ethnic and political factions, the official said.

The top U.N. envoy for Afghanistan, Lakhdar Brahimi, has outlined plans for a two-year transitional government backed by a multinational security force. He is trying to organize a meeting of Afghanistan's many ethnic and tribal groups to decide their own future — hopefully sometime next week.

The United Nations wants it held on "neutral" turf outside Afghanistan. But after the capture of Kabul, the alliance's foreign minister, Abdullah, invited all Afghan factions except the Taliban to come to the capital to debate the new government.

The United States is urging the alliance to commit to the meeting and to compromise on its demand that it be held in Kabul, a U.S. official said in Washington on condition of anonymity. Brahimi's deputy, Francesc Vendrell, arrived in Kabul on Saturday to try to persuade alliance officials.

"It's an extraordinarily difficult situation in which the U.S. and its allies are not in a position to exert control, or even significant influence, over their local allies on the ground whose military victory they smoothed the path for," said former Canadian ambassador David Malone, president of the International Peace Academy, a New York think tank.

Col. Bob Stewart, who was commander of the British U.N. forces in central Bosnia during the Balkans conflict, said the United Nations was moving too slowly.

"Fundamentally, the United Nations should have moved much faster and got people on the ground there," he told BBC.

Greenstock said he didn't think the criticism was fair.

"You can't just move in behind a load of warlords and start taking over a capital city belonging to another country," he said on the radio program. "It all has to be done with legitimacy, with the support of the Security Council, and these things take a few days to organize."

At a closed-door meeting Friday with the "Group of 21" countries that has been seeking peace in Afghanistan, diplomats quoted Brahimi as saying: "Don't tell me speed is of the essence. Tell the factions. And use your influence to get them to the meeting and back off from Kabul."

Ravan Farhadi, an envoy for Rabbani's government, which is still recognized by the United Nations, told the General Assembly the alliance had no intention of monopolizing power.

"All ethnic groups must be equally represented and given a voice," he said Wednesday.

But diplomats say Farhadi has little clout with alliance military forces. And if the northern alliance fails to keep its envoy's promise, it risks "losing the international recognition that the Rabbani government tenuously enjoys at the United Nations," Malone said.

No multinational force has been drawn up yet, but a host of countries have pledged troops. Along with U.S. forces already on the ground, the foreign troops could pressure the northern alliance forces to share power.

Brahimi said Friday that "we will go only as fast as the Afghans are willing to go." But, he said, "the more time is wasted, more problems may crop up and make progress that much more difficult."