George W Bush's campaign is running a new advertisement attacking the White House challenger, John Kerry.
George W Bush has turned up the heat during campaign rallies
The TV commercial accuses Mr Kerry of failing to understand the threat posed by terrorists around the world.
It uses comments made by Mr Kerry to the New York Times where he says he wants to get to a time where terrorism is not the focus but a mere "nuisance".
Opinion polls suggest the two men are in a close race for the presidency, ahead of the 2 November election.
The new Bush ad was produced hours after the Kerry interview appeared in the New York Times magazine.
Asked about what it would take for Americans to feel safe again, Mr Kerry said there needed to be a change in outlook.
''We have to get back to the place we were, where terrorists are not the focus of our lives, but they're a nuisance,'' he said.
''As a former law-enforcement person, I know we're never going to end prostitution. We're never going to end illegal gambling.
"But we're going to reduce it, organised crime, to a level where it isn't on the rise. It isn't threatening people's lives every day, and fundamentally, it's something that you continue to fight, but it's not threatening the fabric of your life.''
Correspondents say that Mr Bush, who has called himself a "war president" and part of whose re-election campaign urges voters not to switch leaders while the country remains at war, paints the struggle against militants as a long-term battle that has defined his presidency.
The script for the new ad accuses Mr Kerry of changing his mind on how best to defeat terrorism, and interprets his comments as equating the war on terror to prostitution.
"Now Kerry says... We have to get back to the place where terrorists are a nuisance like gambling and prostitution... we're never going to end them," an announcer says in the commercial, which is being shown on cable television and from the campaign website.
"Terrorism... a nuisance? How can Kerry protect us when he doesn't understand the threat?"
Kerry campaign spokesman Phil Singer said the ad distorted what had been said.
"It's a dishonest and disingenuous way to campaign for president and another pathetic attempt to play the politics of fear.
"John Kerry is going to hunt and kill the terrorists before they can come after us and no amount of selective editing by the Bush campaign can change that basic fact."
On Monday both candidates were in New Mexico, which was won by Democrat Al Gore in the 2000 election with a majority of just 365 votes out of 575,000 ballots cast.
Mr Kerry touted his energy plan, which he said would help middle-class Americans more than the Bush administration policy "that warms the hearts of their powerful friends and leaves you out in the cold".
John Kerry took his message to churchgoers in Miami on Sunday
A Bush campaign spokesman, Steve Schmidt, accused Mr Kerry of obstructing a national energy policy and of telling voters "whatever he thinks they want to hear".
Both candidates are expected to hone their messages on domestic policy before Wednesday's third and final televised debate.
Across the country, new opinion polls suggest the electorate is still evenly split.
Mr Bush held onto a slim lead with 50% support compared with 46% to Mr Kerry in a new ABC News poll compiled partly after the second debate. The poll had a margin of error of 2.5 percentage points.
A Reuters/Zogby poll released on Monday found a lead for Mr Kerry had grown to three points, with 47% of respondents favouring him to 44% supporting Mr Bush. That survey - taken from Friday to Sunday - had a margin of error of 2.9 percentage points.