PHILADELPHIA -- Democratic presidential nominee Sen. John F. Kerry yesterday launched a fresh assault on the Bush administration, saying the president and his top military brass demonstrated "incredible incompetence" in Iraq by failing to protect tons of explosives, now missing and potentially available to terrorists.

Martha Rial, Post-Gazette In Philadelphia yesterday, presidential candidate Sen. John F. Kerry, left, and former President Bill Clinton stand together amid confetti and cheers at a rally in Love Park in Center City. At right is Philadelphia Mayor John Street. Click photo for larger image. More on Campaign 2004: Election may hang on which way Philadelphia suburbs go Rendell: All absentee ballots in on time will be counted Online exchanges let political junkies bet on candidates they think will win Results mixed in children's presidential election polls Tickets available to Cheney rally What's the meaning of politics in dreams? 2004 Election Voters Guide

The New York Times and CBS News reported yesterday that 380 tons of dangerous explosives had been left unsecured following the fall of Baghdad in 2003. The International Atomic Energy Agency made an official report on the weapons looting yesterday to the U.N. Security Council.

President Bush, in Colorado, struck back without referring specifically to the explosives. He said Kerry was resorting to "the worst kind of Monday-morning quarterbacking," and added that the Democrat's campaign was characterized by "pessimism and retreat."

Kerry was joined at a campaign stop near Philadelphia City Hall by former President Bill Clinton, on the stump for the first time since undergoing heart surgery almost two months ago. After being given a rock star's greeting by the crowd, Clinton said, "If this isn't good for my heart, I don't know what is."

From the moment they took the stage yesterday, Clinton and Kerry double-teamed Bush, criticizing his handling of the economy, the Iraq war, health insurance and education funding.

Kerry, who followed Clinton, invoked the former president's legacy throughout his speech, mentioning Clinton by name at least a dozen times.

Clinton, likewise, spoke at length about himself and his record as president, reminding the crowd that America enjoyed more peaceful times and a better economic climate "the last time we had a Democratic president."

With the election a week away, Democrats are hoping Clinton's campaigning skills can provide a last-minute bump for Kerry, who is betting that Clinton isn't as divisive a political figure as he was when he left office nearly four years ago.

Clinton, looking thin and pale next to Kerry, is popular among blacks, and campaign officials hope his appearances will boost black turnout. Judy Howard, of suburban Philadelphia and a black, said she attended yesterday's rally as much to see Clinton's face as Kerry's.

"Kerry gets better and better," she said, grinning, "but Clinton has always been the bomb."

Yesterday, Clinton accused the Bush team of fear-mongering.

"If one candidate is trying to scare you and the other is trying to get you to think, if one candidate is appealing to your fears and the other one is appealing to your hope, you better vote for the one who wants you to think and hope."

Kerry joined the "fear-monger" chorus, then borrowed liberally from the same playbook, saying the stolen Iraq explosives could be used to kill American troops, blow up airplanes and destroy buildings.

The missing munitions, he said, amount to the "greatest explosives bonanza in history."

Pablo Martinez Monsivais, Associated Press President Bush imitates a baseball batter's stance as first lady Laura Bush looks on at a campaign rally yesterday in Council Bluffs, Iowa. Click photo for larger image.

In several sessions with reporters yesterday on the munitions, the White House spokesman, Scott McClellan, alternately insisted that Bush "wants to make sure that we get to the bottom of this" and attempted to distance the president from knowledge of the issue, saying Bush was only informed of the disappearance within the last 10 days, the New York Times reported. White House officials said they could not explain why warnings from the IAEA in May 2003 about the vulnerability of the stockpile to looting never resulted in action.

Asked about charges from the Kerry campaign that the White House had kept the disappearance secret until The Times and CBS broke the story, Dan Bartlett, the White House communications director said the White House had decided "to get all the facts and find out exactly what happened in this case, and then whether there are other cases." He went on to say, "So doing it piecemeal -- I don't think that would have been the responsible thing." He said that so far, no other large-scale cases of looting of explosives have been found.

Bush, flanked by former New York Mayor Rudy Giuliani in Colorado, told supporters that "the choice is not only between two candidates. It is between two directions in the conduct of the war on terror."

Giuliani, who emerged from the Sept. 11, 2001, attacks a much-loved political leader, lent his popularity to Bush yesterday and repeated the charge that Kerry waffles on issues of national security.

"We can't take a chance [with] someone who can't seem to make up his mind whether terrorism is serious or a nuisance," Giuliani said.

Colorado, considered a swing state, voted for Bush in 2000.

Pennsylvania, meanwhile, voted for Gore. At stake here are 21 electoral votes, the fifth-largest prize in the nation. Kerry will visit the state once more this week, and Bush is scheduled to make three stops.

Because of the potential payoff, both parties are pulling out all the stops to win Pennsylvania. Democratic Gov. Ed Rendell, via a bus tour, is cheerleading for Kerry all week, and former Vermont Gov. Howard Dean will be here.

On the GOP side, Vice President Dick Cheney and Bush's mother, former first lady Barbara Bush, are also scheduled to make appearances.

Combined, the two campaigns have spent about $55 million on advertising in the state.