WASHINGTON, Oct 28: President George Bush has visited Pennsylvania more than 40 times during his four years in office, and almost daily in the past weeks as he intensified his campaign for the White House.

Senator John Kerry, has also staged dozens of rallies there in the past weeks, because this mixed industrial-agricultural eastern state has 21 votes in the Electoral College, and is one of the largest of the dozen or so states up for grabs in Tuesday's presidential election.

So-called battleground states, especially larger ones such as Florida, Pennsylvania, Ohio and Iowa, could tip the scale in favour of either candidate, and the candidates custom-tailor their message depending on what state they are in: health care in Florida with its large population of retirees; jobs in Pennsylvania, a state that has lost several hundred thousand jobs in the last four years; farming in Iowa with its vast crop fields and livestock.

But the issues of war in Iraq and the war on terrorism still top the voter's list.

On Wednesday, Mr Bush and Mr Kerry traded verbal jabs in Lancaster, Pennsylvania, and Sioux City, Iowa - two places which can be barely found on a U.S. map but which weigh more than urban centres like Los Angeles and New York City because of the electoral system.

They were hoping to sway the few voters who have yet to make up their minds in the razor-edge election and mobilize their bases to go to the polls.

Mr Kerry blasted Mr Bush over missing highly powerful explosives in Iraq and failing to take responsibility. Mr Bush fired back, saying the Massachusetts senator was "making wild charges".

"The missing explosives could very likely be in the hands of terrorists and insurgents, who are actually attacking our forces now 80 times a day on average," Mr Kerry told supporters.

"But now, today, we've learned even more. What we're seeing is a White House that is dodging and bobbing and weaving in their usual efforts to avoid responsibility, just as they've done every step of the way in our involvement in Iraq."

Mr Bush dismissed Kerry's charges, saying that the Democrat's advisor admitted to not knowing the facts about the explosives.

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