President Bush said Tuesday that the United States will work for the return of captive Americans in Iraq, but will not submit to terrorist tactics. "We, of course, don't pay ransom for any hostages," Bush said.

Bush spoke on the same day that Al-Jazeera broadcast a video claiming insurgents kidnapped a U.S. security consultant, and the militants displayed a blond, Western-looking man sitting with his hands tied behind his back. The video, which authenticity could not be immediately confirmed, also bore the logo of the Islamic Army in Iraq and showed a U.S. passport and an identification card.

"What we will do, of course, is use our intelligence-gathering to see if we can't help locate them," Bush said.

Bush, speaking to reporters at the end of an Oval Office meeting with the director-general of the World Health Organization, would not comment on reports that the United States runs secret prisons abroad.

"I don't talk about secret programs," Bush said.

But, he said, the United States does not torture and will do everything in its legal power to protect Americans while abiding by U.S. law.

Human rights organizations and legal groups, both in the United States and abroad, have accused the United States of allowing a practice known as "rendition to torture," in which suspects are taken to countries such as Egypt and Saudi Arabia where harsh interrogation methods are used. The U.S. has denied that tactic, a denial Bush repeated Tuesday.

"We do not render to countries that torture," he said.

Secretary of State Condoleezza Rice, who is traveling in Europe, has faced tough questions about whether the United States houses suspected terrorists in secret prisons that violate European legal and human rights guarantees. The general issue of U.S. treatment of detainees in the war on terror has been an irritant in relations with Europe and other parts of the world since shortly after the Sept. 11, 2001, attacks.

It gained new immediacy last month with a Washington Post report claiming the U.S. ran prisons in Thailand, Afghanistan and Eastern Europe, and claims by Human Rights Watch that it had tracked CIA flights into Eastern Europe.

Asked about Democratic National Committee Chairman Howard Dean's comments that the United States won't win in Iraq, Bush dismissed him as a politician trying to "score points." Bush said he knows the United States will win, and the troops need to hear that message.

"Of course, there will be some pessimists and some people playing politics with the issue," Bush said. "But, by far, the vast majority of people in this country stand squarely with the men and women who wear the nation's uniform."

Bush said the best way to make Iraq a peaceful society is to continue to spread democracy.

"There are terrorists there who will kill innocent people and behead people and kill children, terrorists who have got desires to hurt the American people," he said. "The more violent they get, the clearer the cause ought to be, that we're going to achieve victory in Iraq and that we'll bring these people to justice. We will hunt them down, along with our Iraqi friends, and at the same time spread democracy."

Bush thanked his guest from the WHO, Lee Jong-Wook, for preparing for a possible pandemic of avian flu. "This is a remarkable collaborative effort to do our duty to help people," Bush said.