US President George W. Bush and his Democratic rival John Kerry traded accusations Wednesday over the missing of nearly 380 tons of explosives in Iraq as the two candidates intensified their efforts to break the deadlock for the election six days before the voting.

Bush brought up the matter of the missing explosives for the first time in a speech in Lititz, Pennsylvania, breaking an unusual silence since its revelation on Monday. He accused Kerry of "making wild charges."

"The senator's denigrating the action of our troops and commanders in the field without knowing the facts," he said. " Unfortunately, that's part of a pattern of saying almost anything to get elected."

"A political candidate who jumps to conclusions without knowing the facts is not a person you want as your commander in chief," Bush said.

In the last two days, Kerry has seized on the issue to question Bush's fitness as commander in chief, saying the president's silence confirms his failure in handling the war.

Stumping the Midwestern battleground of Iowa on Wednesday, Kerry continued to blast the president for failing to secure the explosives that disappeared from a military installation south of Baghdad soon after the US invasion of Iraq.

"What we're seeing is this White House dodging and bobbing and weaving in their usual effort to avoid responsibility, just as they've done every step of the way in our involvement in Iraq," Kerry said.

New polls suggested that the race was still deadlocked in Florida, Ohio and Pennsylvania, the three most important battlegrounds and also in other smaller states.