Washington ? President Bush Saturday urged the United Nations to “show some backbone” and move against Iraqi leader Saddam Hussein in a last chance to “prove its relevance.”

“Enough is enough,” Bush declared. “The U.N. will either be able to function as a peacekeeping body as we head into the 21st century, or it will be irrelevant. And that’s what we are about to find out.”

President Bush met with Italian Prime Minister Silvio Berlusconi, left, Saturday at Camp David to discuss Iraq.

Following up his challenge to the United Nations Thursday in New York, Bush pressed ahead Saturday with even harsher words as he met at Camp David with Italian Prime Minister Silvio Berlusconi.

The president has laid out a detailed case against Saddam, accusing him of repeated violations of 16 U.N. resolutions since the 1991 Persian Gulf War and warning that he is developing not only chemical and biological weapons but also nuclear ones.

“The international community must work together to prevent this from happening,” Bush told reporters Saturday at Camp David, the presidential retreat outside Washington in Maryland’s Catoctin Mountains. “So, this is a chance for the United Nations to show some backbone and resolve as we confront the true challenges of the 21st century.”

If not, the president was unequivocal: “If we have to deal with the problem, we’ll deal with it.”

And Vice President Dick Cheney was just as adamant.

“If they don’t,” he said on CNN’s “Novak Hunt & Shields” Saturday, “then the United States will be left with no choice but do so.”

Berlusconi, who stood at Bush’s side during a short meeting with reporters at the Camp David helipad, commended Bush for taking his case against Iraq to the U.N. Security Council and urged the world body to act.

“The United Nations cannot continue to see its image undermined and its solutions flaunted,” Berlusconi said.

The White House described Saturday’s meeting as a wide-ranging discussion that also dealt with the continuing volatility in the Middle East and the war on terrorism, particularly rebuilding Afghanistan.

Sean McCormack, a spokesman for the National Security Council, said the president welcomed Berlusconi’s “strongly supportive” comments, noting the president had not yet decided that the United States alone would go to war against Iraq.

“All options are on the table,” McCormack said.

Berlusconi, who has been wary of a unilateral U.S. strike, said he had come to Camp David representing a country, “which is a loyal and faithful ally.”

“So I will be able to speak as a friend, speak truthfully in order to find, as usual, common solutions and common positions.”

He did not elaborate, though, on exactly what common ground he was seeking, nor did he speak directly to the possibility that the United States might strike Iraq on its own.

The Italian prime minister was the second world leader to visit Bush at Camp David in a week. British Prime Minister Tony Blair was there last weekend, and Bush conferred with Canadian Prime Minister Jean Chretien in Detroit on Monday and many more world leaders, either personally or by telephone, last week in Washington and New York.

Other than Britain and Israel, Bush has found little support around the world for unilateral U.S. military action. But he pointedly noted Saturday in his weekly radio address that Berlusconi was joining the leaders of Britain, Spain and Poland, who all have reached the same conclusion: “that Saddam Hussein has made the case against himself.