Hamid Karzai, Afghanistan's interim leader, with Secretary of State Colin L. Powell at a meeting in Tokyo Monday on aid for his country.

Prime Minister Junichiro Koizumi of Japan with Afghanistan's interim leader, Hamid Karzai, during a meeting in Tokyo on Afghan relief.

Addressing the opening session, Secretary of State Colin L. Powell said the first-year contribution — close to one-fifth of the $1.7 billion the United Nations has estimated will be needed in the first year — will be used for programs including agricultural, health, security and counter- narcotics efforts as well as refugee assistance.

"President Bush has made it clear that the United States will not abandon the people of Afghanistan," Secretary Powell said, adding that it was up to the world to help Afghans "make a future worthy of their highest hopes." He added: "Let us build on the richness of Afghanistan's past. Let us build a new history that will protect and ennoble us all."

But on the first day of the two-day conference, questions remained about how much money will be raised, how it will be administered and whether it will be enough to help a country devastated by two decades of war.

"Today in Afghanistan, a window of opportunity is opening," Mr. Annan said. "Through it we can see a country drawing back from the brink of devastation."

But, he warned, "What happens next is by no means predetermined, and success cannot be taken for granted. More than once in recent years, countries have sunk back into conflict just when peace seemed to be taking hold. We are here today to do our part in making sure that does not happen in Afghanistan."

The leader of the interim Afghan government, Hamid Karzai, brought a hush over the room when he departed from his list of his country's pressing needs to note that Afghanistan remained a world away from the brightly lit, westernized hotel ballroom in which he spoke.

"I stand before you today as a citizen of a country that has had nothing but disaster, war, brutality and deprivation against its people for so many years," Mr. Karzai said. "So when I read this paper, which does not contain much sentiment, please recognize" that "what you see here isn't what you see in Afghanistan."

Bush administration officials said that the $296 million that Secretary Powell announced today would come from a reallocation of funds already appropriated and so could be delivered quickly. About $111 million is left from $320 million in aid that was not needed for Afghan refugees.

The proportion of the American contribution is somewhat below the typical pattern of the United States' contributions — usually about 25 percent. But administration officials have repeatedly emphasized that because Washington has borne the bulk of the cost of the war against the Taliban, it expects other nations to play a greater role in peacekeeping and rebuilding.

Other nations were expected to pledge comparable amounts. Prime Minister Junichiro Koizumi of Japan said his nation would pledge up to $250 million for the first year, and a like amount in the year and a half after that. Japan is a co-chair of the conference, along with the United States, Saudi Arabia and the European Union nations.

European Union officials said they expected to pledge about $500 million for the first year, but officials have suggested in the past that some of that could be in in-kind contributions. Saudi Arabia said it would pledge $220 million over three years.

American officials cautioned that sorting who gives how much would be complicated because of multiyear contributions. "This won't only be apples and oranges — it will be clementines and pineapples," one senior administration official said.

Speakers emphasized that the effort would be long term.

"In order to eradicate terrorism, we must eliminate conditions that allow terrorism to take root," Mr. Koizumi said. "To do so, it is essential that a peaceful and stable Afghanistan be built. This cannot be done in one or two years."

The United Nations and World Bank put the estimated 10-year reconstruction costs at about $15 billion, though officials caution that the estimates are tentative.

Afghanistan's needs are so staggering that some quibble with the word "reconstruction," saying that the task at hand is in fact an effort to build a modern state where there was none before. Only 6 percent of girls and 20 percent of boys go to school, according to the United Nations. There are few paved roads. Agriculture is suffering from years of recurrent drought, and the countryside is peppered with land mines and awash in weapons.

"Every Afghan from Hamid Karzai to the man on the street corner says his first priority is security," said Mark Malloch Brown, administrator of the United Nations Development Program, in an interview.

"This is a country with a terrible history of sheer absence of law and order. When they say security they don't necessarily mean blue helmets, but neighborhood policing, people in the streets.

He added: "The second thing is a government. The critical thing here is to reestablish a government that people feel they get benefits from and that they can place their trust in. There hasn't been that kind of government for 20 years, and more than half of Afghans are under 20."

On Sunday, Mr. Brown's agency arranged the delivery of $6 million to Kabul to finance Afghanistan's bankrupt interim government's operating budget for the next month. Realistically, he said, the interim government of Mr. Karzai would have no meaningful income for the next two years, during which the World Bank, the United Nations and the Asian Development Bank will pay salaries and oversee government spending.

Today, Mr. Karzai pledged to hire a "reputable international firm to audit our expenditures on a regular basis," and insisted: "The elimination of corruption is one of my top priorities."

In recent years, the conference host, Japan, has provided large-scale financial assistance in international crises, but its budget was recently cut by 10 percent, a victim of economic crisis and falling public support for spending overseas.

"We must do a better job of promoting the concept of Japan being useful to the world," said Hasashi Owada, a former Japanese representative to the United Nations. "While I think it is important that we make a financial contribution, what I think is more important is that Japan be involved in doing things that are helpful to Afghanistan. We should be involved politically, and we should be involved in reconstruction activities, not just in providing financial assistance."