White House officials are so pleased with Secretary of State Colin Powell's presentation at the United Nations Wednesday that they called off all public appearances, including the press secretary's daily briefing, saying that adding anything else would detract from the impact of Powell's remarks.

One White House official said Powell "hit it out of the park" and made a forceful, compelling case.

"Only the unconvincable could remain unconvinced," the official said.

Several lawmakers on Capitol Hill agreed.

"The import of Secretary Powell's message is compelling and chilling," House Majority Leader Tom Delay said in a statement Wednesday.

"For Saddam Hussein's appeasers, no showing of diabolical crimes, documented militarism and pursuit of mass terror weapons will ever constitute sufficient, so-called 'evidence' to confront his tyrannical regime. For people of common sense, no such additional evidence is needed: Terrorists and terror states have to be eliminated."

Powell presented "a compelling argument and detailed evidence that should persuade anyone capable of being persuaded that Saddam continues to develop weapons of mass destruction," said Rep. Henry Hyde, chairman of the House International Relations Committee.

Powell spoke for just under 90 minutes Wednesday, in which he presented evidence that Iraqi leader Saddam Hussein is not disarming but rather flaunting his defiance in front of the international community.

Saying Saddam's weapons of mass destruction will only "sow chaos and death," Hyde said, "We can be certain that if terrorists acquire these weapons, they will use them, and we may find ourselves mourning the deaths of millions, not thousands."

In his remarks, Powell said that if the United Nations decides to turn a blind eye to the ultimatum posed by U.N. Security Council Resolution 1441 and allows Saddam to continue to violate disarmament promises, the United Nations will be reduced to a "meaningless institution."

Sen. George Allen, R-Va., called Powell's intelligence "clear and convincing evidence" and said the onus is on Saddam to own up to Iraq's weapons program and lead inspectors to stockpiles.

Inspectors are "chasing around as best they can" to find the weapons, but "it's not, again, a game of find a needle in a haystack in Iraq. It's not for us to find," Allen said.

But several lawmakers, while praising Powell's performance, said that the results don't mean that war should be the next course of action.

"The question is whether war now is the only way to rid Iraq of these deadly weapons. I do not believe it is," said House Democratic Leader Nancy Pelosi of California. "Before going to war, we must exhaust all alternatives, such as the continuation of inspections, diplomacy and the leverage provided by the threat of military action."

Sen. Joe Biden, D-Del., ranking member of the Senate Foreign Relations Committee, said that before any military force is used, the United States should seek U.N. support.

"While we can win the war on our own, we are much better off with the support of the United Nations," Biden said, adding that post-war efforts will require help from "as many countries as possible."

President Bush has said repeatedly that he will collect a coalition of the willing to topple Saddam if the United Nations fails to see the severity of his breaches of international rule.

On Wednesday, Lithuania's prime minister came out in support of U.S. policy toward Iraq, joining nine other East European nations who vowed to back the United States. Seven of those countries, including Lithuania, were invited to join NATO last year. The other three are seeking membership.

Last week, eight European leaders announced their support for U.S. policy.

Biden and Sen. Edward Kennedy, D-Mass., said that Bush needs to explain to the American people what war with Iraq will require in terms of monetary and personnel commitment.

"I don't think many Americans understand the scope and the magnitude" of what a war will mean, Biden said.

"What is going to be the human cost in terms of civilian causalities as a result of the greatest release of precision weaponry let loose on Baghdad?" Kennedy asked during an afternoon press conference. "These dangers are a concern of the American people and the American people want to hear from their president" before we "put our troops in harm's way."

Several lawmakers warned that to do nothing creates a greater risk.

"The evidence proves that Saddam Hussein has a loaded gun pointed at the civilized world. It is time to take that loaded gun away from this evil tyrant," House Speaker Dennis Hastert, R-Ill., said.

"In the post-Sept. 11 environment, I do not believe we can risk the chance that Saddam Hussein will seek to link his efforts to secure weapons of mass destruction with those of terrorists seeking to do harm to innocent civilians in the U.S. and elsewhere around the world," Sen. Olympia Snowe, R-Me., said in a statement.

"The world community should join the United States in insisting on full compliance with this resolution -- or, if necessary, action to enforce those resolutions with military force."

Fox News' Wendell Goler contributed to this report.