President Bush and Sen. John F. Kerry exchanged angry charges again today over missing Iraqi munitions as their campaigns headed toward a final showdown before the voters next Tuesday.

In a speech in Saginaw, Mich., Bush accused his Democratic challenger of "attacking the actions of our military in Iraq," a charge that the Kerry campaign called "hypocrisy."

For the Kerry campaign, a report by the International Atomic Energy Agency to the U.N. Security Council Monday on the missing explosives has buttressed Kerry's arguments that the Bush administration has mismanaged the war in Iraq, in part by failing to dispatch enough troops to secure sensitive sites and stop looting.

For the fourth straight day, the Massachusetts senator today flayed Bush over the nearly 380 tons of missing high explosives, saying in Toledo, Ohio, that it was time for Bush to take responsibility for his mistakes.

"Our troops in Iraq are doing a heroic job," Kerry said. "The problem is our commander in chief isn't doing his."

That distinction did not stop Bush today from trying to cast Kerry's criticism as an attack on the U.S. military.

Delivering a broad indictment of Kerry's fitness to be president, Bush told supporters in Saginaw, "Senator Kerry changes positions because he's willing to say anything he thinks will help him politically at the time." He said Kerry "has been on the wrong side of the defining national security and domestic policy debates for the last two decades."

Although Kerry was "supportive" when former Iraqi president Saddam Hussein was captured by U.S. forces last December, Bush said, "When the going got tough and when we faced determined opposition and things weren't quite so popular, the senator suddenly wasn't quite so supportive. In fact, he changed his mind entirely, deciding it was the wrong war at the wrong place at the wrong time."

Referring to the missing explosives, Bush said, "This week Senator Kerry is again attacking the actions of our military in Iraq, with complete disregard for the facts. Senator Kerry will say anything to get elected. The senator's willingness to trade principle for political convenience makes it clear that John Kerry is the wrong man for the wrong job at the wrong time."

Kerry noted that U.S. forces were not ordered to secure the Qaqaa storage site where the high explosives were stored and quoted the administration's former chief weapons inspector as saying it was likely that these explosives were now being used against U.S. troops.

"The president's shifting explanations and excuses demonstrate, once again, that this president believes the buck stops anywhere but his desk," Kerry said in a statement. He said Bush should act more like former president John F. Kennedy, whose name Bush has invoked lately in seeking crossover votes from Democrats, and "take responsibility for his actions."

Kerry also seized on Bush's statement yesterday that "a political candidate who jumps to conclusions without knowing the facts is not a person you want as your commander in chief."

"I agree," Kerry said. "George Bush jumped to a conclusions about 9/11 and Saddam Hussein. He jumped to conclusions about weapons of mass destruction and rushed to war. He jumped to conclusions about how the Iraqi people would receive us. He not only jumped to conclusions -- he ignored the facts."

"According to George Bush's own words, he shouldn't be our commander in chief," Kerry said.

The Kerry campaign also criticized a comment this morning by former New York mayor Rudolph Giuliani, who has been stumping for Bush. Asked about the missing explosives on the "Today" show, Giuliani said, "No matter how you try to blame it on the president, the actual responsibility for it really would be for the troops that were there. Did they search carefully enough? Didn't they search carefully enough?"

Referring to Bush's charge in Michigan today, Kerry campaign spokesman Phil Singer said in a statement, "George Bush's hypocrisy knows no bounds. On the same day that his top surrogate blames the troops for the missing explosives, the president has the audacity to cast stones at John Kerry. If George Bush understood what it means to be commander in chief, he'd understand that this is his responsibility and wouldn't be dispatching his allies to denigrate our troops."

Retired Army Gen. Wesley K. Clark, a Kerry supporter who competed with him in this spring's Democratic primaries, said it was "insulting and cowardly" of Bush to "send Rudolph Giuliani out on television to say that the 'actual responsibility' for the failure to secure explosives lies with the troops. . . ." In a statement, Clark said, "This was a failure of civilian leadership" in not ordering the munitions secured and not providing sufficient troops and equipment to do the job. He said the troops "deserve a commander in chief who supports them . . . not one who gets weak knees and shifts blame for his mistakes."

Kerry's running mate, Sen. John Edwards of North Carolina, also leaped into the fray this morning while campaigning in Minnesota, Washington Post staff writer John Wagner reported.

Appearing at the University of Minnesota at Duluth, Edwards said Giuliani "blamed the troops" for the missing explosives and "couldn't be more wrong." Edwards said, "Our men and women in uniform did their job. George Bush didn't do his job." He said the episode is part of a pattern.

"Over and over, for the past four years, George Bush refuses to take responsibility," Edwards said. "It is time for him to step aside."

Following the morning appearance, Edwards was headed to Iowa for a pair of rallies in that battleground state. He was to be joined at both events and on his plane by rock star Jon Bon Jovi.

While continuing to hit Bush hard on the missing explosives, Edwards has also argued in recent days that the election presents voters with stark choices on domestic issues as well, including health care, the environment and tax policy. In Duluth, Edwards said that, contrary to claims by Bush, Kerry would offer more tax relief to the middle-class, through credits for child care, health care and college tuition.

"George Bush is out there on the campaign trail saying things that aren't true," Edwards said. He said the choice between Kerry and Bush represented a choice between tax cuts for the middle-class and tax cuts for millionaires.

In Toledo, Kerry took the stage with a Boston Red Sox baseball cap on his head in honor of his hometown team's victory last night in the World Series for the first time in 86 years.

He recalled that a year ago, when his campaign was in trouble, a caller had told a radio station that "John Kerry won't be president until the Red Sox win the World Series."

Said a delighted Kerry, "Well, we're on our way. We're on our way."

From Toledo, Kerry flew to a rally in Madison, Wis., where he was appearing with rock singer Bruce Springsteen. A crowd of tens of thousands of people gathered at the Wisconsin State Capital for the event, which featured a performance by Springsteen.

Kerry was later scheduled to return to Ohio for a rally in Columbus.

After his appearance in Saginaw, Bush also headed to Ohio for rallies in Dayton and Westlake, followed by a trip to Pennsylvania.

Vice President Cheney, meanwhile, was campaigning today in Wisconsin, Minnesota and Iowa.

In a meeting with community leaders in Schofield, Wis., Cheney referred to an ABC News report that some of the missing Iraqi munitions were already gone before American forces invaded the country.

"Kerry is just dead wrong," he said. "We know now from documents that ABC revealed last night that in January, three months before our guys had arrived . . . upwards of 151 tons had already been removed." He repeated Bush's charge that Kerry was criticizing the military and said, "Frankly, I think it's a cheap shot."

In a rally later in International Falls, Minn., a tiny blue collar town a half mile from the Canadian border, Cheney called Kerry's criticisms of Bush over the missing explosives "an assault on the capability and competence of our troops and commanders."

In Vienna, Austria, meanwhile, the International Atomic Energy Agency said it had warned the United States about the vulnerability of explosives stored at Qaqaa after Iraq's main Tuwaitha nuclear complex was looted in April 2003, the Associated Press reported.

The U.N. agency said Monday that 377 tons of high explosives, including compounds that could be used to trigger nuclear bombs, were missing from Qaqaa. Officials of the U.S.-backed Iraqi interim government have said the materials were taken after the April 9, 2003, fall of Baghdad to U.S. forces, and they have blamed lax security for the looting.

The IAEA today also sought to clarify the ABC News report, which cited IAEA inspection documents as showing that although Iraq had declared 141 tons of RDX explosives at Qaqaa in July 2002, the site held only three tons when U.N. inspectors checked it in January 2003. ABC said 138 tons thus may have been removed from the Qaqaa long before the March 2003 invasion.

But an IAEA spokeswoman, Melissa Fleming, said most of the RDX -- about 125 tons -- was kept at al Mahaweel, a storage site under Qaqaa's jurisdiction located outside the main Qaqaa site, AP reported. She also said that Iraq had previously reported using about 10 tons of the material for non-prohibited purposes between July 2002 and January 2003, AP said. Fleming said IAEA inspectors verified the RDX inventory at Mahaweel on Jan. 15, 2003.

In Wisconsin, Cheney also repeated a charge that Saddam Hussein was connected to the al Qaeda terrorist network of Osama bin Laden, saying that Hussein "had a relationship with al Qaeda." The commission that investigated the Sept. 11, 2001, terrorist attacks concluded that there had been contacts between Hussein's government and al Qaeda, but no collaborative relationship and no Iraqi connection to the Sept. 11 attacks.

Outside the restaurant where Cheney met with local leaders, chants of "Four More Years" by a crowd of Bush supporters clashed with shouts of "Five More Days" from Kerry supporters across the street.

In International Falls, Cheney was cheered this afternoon by paper mill workers and loggers as he called Kerry a politician who will "do and say anything" for political purposes.

Cheney contrasted that image with a depiction of President Bush as a steadfast and confident leader who is committed to "making us safer, more prosperous and more secure."

That was exactly what Bill Knapp, 51, a night shift worker at the nearby Boise-Cascade paper plant, wanted to hear. Bush "does what needs to be done, even if it isn't always popular," said Knapp, whose 20-year-old son, an Air Force reservist, is heading to Iraq in February.

"If my son dies for our country, there is no greater honor," he said.

Layton, traveling with Cheney, reported from Wisconsin and Minnesota.