Secretary of State Colin L. Powell said today in his clearest terms yet that force may be needed to disarm Iraq, and he called on world leaders to stand together in a "great coalition" to prevent war and, if necessary, to fight one.

The likelihood that Iraq's president, Saddam Hussein, will continue to defy the U.N. Security Council is strong, Powell said in a speech at the World Economic Forum. Powell said Hussein has failed to account for his weapons programs and asserted that international weapons inspectors will not be able to find and remove munitions without Iraqi compliance.

"We are where we are today with Iraq because Saddam Hussein and his regime have repeatedly violated the trust of the United Nations, his people and his neighbors, to such an extent as to pose a grave danger to international peace and security," he said.

Officials expect the chief U.N. weapons inspector, Hans Blix, to report to the Security Council on Monday that the Iraqi government continues to refuse to take an active role in the inspections process and that questions remain about the country's possession of prohibited weapons of mass destruction.

The U.N. report will come one day before President Bush delivers his State of the Union address, in which he is expected to define the case for military action against Iraq at a time when polls show Americans have rising doubts. U.S. officials have also sought to shore up support for military intervention among allies who say the Bush administration is moving too quickly toward war and has not given inspectors enough time.

In Davos, Powell sought to answer critics who question U.S. motives and the pace of the administration's drive against Hussein. Powell said the United States would not rush to judgment when the U.N. weapons inspectors deliver their report. "But clearly," he said, "time is running out."

To people who urge giving U.N. inspectors additional months to scour the country for weapons of mass destruction, Powell said, "it is not a matter of time, it is a matter of telling the truth."

The Bush administration has said it is prepared to act without U.N. approval, if necessary, to disarm Iraq and overthrow Hussein. But with Powell taking the diplomatic lead, the administration is trying to assemble a broader coalition that can intimidate the Iraqi leader, inspire a coup against him or defeat him militarily if he resists.

Powell made his most dramatic comments in response to a question about how the terrorist attacks on Sept. 11, 2001, had affected him personally. He spoke with emotion about his realization that the United States was at war, the terrorist enemy was real and the Bush administration would have to act, even on a day "when our anxieties would well up and our fears would well up."

"We are probably approaching one such moment now," Powell said. "We will have to take that next step, and history will judge us as to whether or not we have the strength, the fortitude and the willingness to take that next step."

At the annual conference of the World Economic Forum, whose theme this year is "Building Trust," Powell said the United States can be trusted to use its enormous economic, political and military power wisely. In an effort to repair recent damage to the U.S. reputation, he pledged to work closely with Europe, "home of our closest friends and partners."

Powell said pointedly, however, that the 15 U.N. Security Council members, who in a resolution in November unanimously threatened "serious consequences" against Iraq, knew they would be asked to approve military force if Hussein failed to comply.

"There was no confusion on this point," he said. "Everybody knew what that meant."

He said the administration would reveal more of its evidence about Iraq's weapons programs, but he called the existing public case "persuasive."

Powell said Hussein has "clear ties to terrorist groups including al Qaeda," and said the longer the international community waits, the greater the chance that Hussein will share his weapons and technology or use them again. Hussein in the 1980s used poison gas against Kurds in northern Iraq and in neighboring Iran.

"The support of U.S. intelligence and the intelligence of other nations can take the inspectors only so far," Powell said. "Without Iraq's full and active cooperation, the 100 or so inspectors would have to look under every roof and search the back of every truck in a country the size of California to find the munitions and programs for which Iraq has failed to account."

When a representative of Amnesty International asked Powell whether the potential benefits of invading Iraq were worth risking a humanitarian calamity in the country and the region, he replied that Iraqis are suffering now and that a post-Hussein Iraq would offer them greater opportunities.

Powell again defended the use of military force in response to a question from George Carey, the former archbishop of Canterbury, who asked about the relative merits of "hard power," or military force, in contrast to "soft power," such as economic assistance, international agreements or the force of example.

"There comes a time when soft power or talking with evil will not work -- where, unfortunately, hard power is the only thing that works," Powell said. "There are still leaders around who will say you do not have the will to prevail over my evil, and I think we are facing one of those times now."

Secretary of State Colin L. Powell said "time is running out" for Iraq.