Secretary of State Colin Powell encouraged ambassadors and other foreign diplomats Tuesday to stress to their governments the importance of political leadership in fighting AIDS.

"Each of us here today has the power to act. The positions we hold in our governments give our voices resonance at home and abroad,'' he told the group gathered at the State Department's ceremonial reception room. "We can and must use our voices to convince others of the urgency and gravity of this global problem.''

Every nation, regardless of its size, economic status or political strength, is vulnerable to the HIV/AIDS epidemic, Powell said.

"HIV doesn't just destroy immune systems, it also undermines the social, economic and political systems that underpin entire nations and regions,'' he said. "The disease spreads fastest in places under stress, weakening already fragile support systems beyond the breaking point.''

The State Department invited 164 governments accredited in Washington to hear Powell's speech, and 86 nations sent representatives.

Health officials estimate there are 42 million people worldwide who are infected with the HIV virus that causes AIDS. About 75 percent of them live in sub-Saharan Africa. State Department officials could not immediately comment on whether diplomats from that region attended Tuesday's event.

Powell called for those gathered to ensure that the fight against AIDS is a top priority for their governments. He stressed that world leaders must be educated about how the disease spreads, how it can be prevented and how those infected can be treated.

"It is critically important that accurate, lifesaving information reaches all of the people in our countries. Like great evils, AIDS feeds on ignorance and fear,'' he said.

He cited as an example Ugandan President Yoweri Museveni, who recognized early in his tenure the threat AIDS posed to the country's national security. Museveni personally oversaw the creation of a joint center for research studies and, as a result, the nation has reduced infections by 50 percent since 1992.

Health and Human Services Secretary Tommy Thompson, who joined Powell at the speech, pointed out that the United States was the first government to contribute to the Global Fund to Fight AIDS. He said that the United States, by pledging $500 million over two years, is also the fund's largest contributor.

"The United States is well aware that investing in global health is not only a matter of increasing economic growth or improving political stability, it will help us do nothing less than save the next generation,'' Thompson said.

But Paul Davis of the AIDS advocacy group Health GAP called the U.S. contribution meager compared with other nations. He also mocked the administration's insistence that it is the largest single donor.

"First, that's not saying much — contributions are grossly inadequate, and the Global Fund needs $8 billion more in the next two years,'' said Tom Hart, director of government relations for the Episcopal Church. "Second, it's a very misleading claim, because European Union countries give far more as a share of their economy.''

Hart said the United States has an economy that matches those of European nations combined, and yet the EU has committed $1.1 billion to the AIDS fund.

"It's past time for the Bush administration to stop saying AIDS is a crisis and start treating it like one,'' Health GAP's Davis said.