WASHINGTON (AFP) - With just one month left before the US presidential election, candidates turned up the heat on the campaign trail, as television ratings for the debut presidential debate showed interest in the race running high.
Bush was due to stump once again in the battleground state of Ohio while Kerry continued campaigning in storm-battered Florida, two days after the rivals met up in the southeastern state for the first of three presidential debates.
Some 62.4 million US viewers tuned in to watch Bush and Kerry debate foreign policy and national security on Thursday, making it the most watched presidential debate since 1992, when Bush's father took on Democrat Bill Clinton, according to Nielsen Media Research.
Viewer figures for Thursday's debate also surpassed by nearly 16 million those for the first debate four years ago between Bush and then-Vice President Al Gore, the ratings firm said.
Debates held ahead of the 1992 presidential election were said to have boosted support for Clinton in his ultimately successful challenge of incumbent president George Bush, father of the current president.
A record 62.4 million people watched the initial presidential debate in 1992, which featured maverick independent candidate Ross Perot as well as Clinton and Bush.
Snap polls said Kerry won the contest Thursday but experts warned it would take days to accurately assess the exchange's impact on the hard-fought campaign.
They also agreed that the close-fought debate raised the stakes for the second presidential face-off, set for October 8.
A third debate is scheduled for October 13, with voting taking place on November 2.
In 1992, the audience grew for the second and third debates, to 69.9 million and 66.9 million respectively, according to Nielsen figures cited by the Commission on Presidential Debates, which produces and sponsors the events.
Bush sharpened attacks on Kerry's Iraq war strategy Friday, a day after the Democrat's strong showing in their first debate.
Bush used language that was often harsher than when he was face to face with Kerry, seizing on his foe's comment that preemptive US military action like the invasion to oust Saddam Hussein ought to pass a "global test" for legitimacy.
"The president's job is not to take an international poll. The president's job is to defend America," the Republican incumbent said. "The use of troops to defend America must never be subject to a veto by countries like France."
Bush's comment, made to cheering supporters in the crucial state of Pennsylvania, aimed to stoke still smoldering anger among Republicans over France's opposition to the March 2003 invasion of Iraq.
Aides to Kerry, who was on a two-day swing aimed at converting post-debate momentum into votes in Florida -- the state that decided the last election in favour of Bush -- countered that the president had taken his comments out of context and diagnosed the move as desperation.
"If you rely on a half-sentence to attack your opponent, it's proof youre not telling the whole truth, youre distorting a debate you lost," said Kerry spokesman David Wade.
"It's evidence of how much their candidate is flailing."
The president wooed also voters in New Hampshire Friday, working to preserve a steady lead in national polls and a thin edge in many of the swing states that will decide the November 2 election.
A Gallup poll for CNN gave Kerry a 46 percent to 37 percent debate win over the president but the survey said Bush still had the support of 51 percent of voters against 47 percent for Kerry.
The rivals meet up again in St Louis, Missouri next Friday. Before then, the US public will get a chance to see their running mates, Vice President Dick Cheney and Senator John Edwards, go head to head at a forum in Ohio Tuesday.