Condoleezza Rice shakes hands with Afghan President Hamid Karzai after a press conference at Claridges, London

Secretary of State Condoleezza Rice Monday reaffirmed the U.S. commitment to the Afghan government, saying the two countries' futures are "inextricably linked." She met Afghan President Hamid Karzai in London on the eve of the opening of an international donors conference for Afghanistan.

There has been anxiety among Afghan officials and others about U.S. plans to withdraw some 2,500 troops from Afghanistan in the next few months in favor of replacements from several other NATO countries.

But at a joint news appearance with President Karzai, the secretary of state delivered a strong reaffirmation of the U.S. commitment to that country, saying the peaceful future of the United States is "inextricably linked" to that of Afghanistan.

The secretary promised there would be no repeat of the situation that followed the end of the Russian occupation of Afghanistan in 1989, when Western governments turned their attention elsewhere and the country was left to the Taleban and al-Qaida.

"The United States has a robust commitment to Afghanistan, militarily, politically, economically," Rice said. "And we are going to continue that robust presence, because as long as the people of Afghanistan need American partnership, they're going to have it. We made the mistake once before of leaving Afghanistan, and not only did Afghans pay for it, but Americans paid for it on September 11 [2001]. We're not going to make that mistake again."

The secretary of state said trimming the U.S. military presence will still leave some 16,000 American troops in the country, by far the largest foreign contingent.

She said there should be less focus on troop numbers and more on what she said was the U.S. commitment with the Kabul government "to get the job done."

That, she said, includes creating an Afghanistan with capable security forces that can fight terrorism and its narcotics problem, and allow peaceful development for its people.

En route to London Sunday, Secretary Rice said the United States will announce a significant new financial commitment to Afghanistan at the two-day donors conference that opens here Tuesday.

The United States has provided nearly $10 billion in economic military aid to Afghanistan since it led the invasion of the country in October 2001 that ended Taleban rule.

The 60-nation conference is to produce what's being termed a "compact" between Afghanistan and major contributing countries, under which the Kabul government will commit to specific goals over the next five years in security, governance and economic development.