The US homeland security secretary says there is no intelligence pointing to attacks on election day and has urged Americans to vote in confidence.
Ridge said there was no known threat to target election day
Tom Ridge said there was no need to raise the alert level, despite Osama Bin Laden's threat of more attacks.
But the threat has pushed national security back to the top of the agenda in the presidential campaign.
The main candidates, who are chasing votes in several key states, have traded pledges to keep America safe.
President George W Bush and his Democratic challenger John Kerry are both campaigning in Ohio and Florida on Sunday, with Mr Kerry making an additional stop in New Hampshire.
They are trying to court every last voter they can in the eight to 10 states that are so close it makes the outcome on Tuesday difficult to predict.
Between them, the two men visited Michigan, Florida, Ohio, Wisconsin, Iowa, and Minnesota on Saturday.
Interviews with both candidates were aired on the Spanish-language variety show Sabado Gigante in the evening, as they targeted the key 40-million strong Hispanic constituency.
They spoke mainly in English with some phrases in Spanish.
Mr Kerry indicated a liking for guitar-playing and flamenco music, while Mr Bush said he liked to pray.
The appearance on al-Jazeera TV of a video statement from Bin Laden has thrust US national security back to the top of the agenda.
In the video, aired on Friday, a calm, measured Bin Laden addressed Americans directly, telling them the reasons behind the 11 September attacks still remained.
But Mr Ridge told reporters there was no known threat of attack during the elections.
"It's important to know... there is no specific intelligence that targets election day, polling places and the like," he said.
"First of all we want to make sure that people feel safe and comfortable about going to vote."
Mr Ridge said security measures had been bolstered, but there were no plans to raise the terror threat level from yellow or "elevated".
Nonetheless, both candidates have been responding to the Bin Laden threat.
The BBC's Rob Watson in Washington says Republicans hope - and Democrats fear - that it will remind any undecided voters of the war on terrorism, the one issue where the president enjoys a clear and commanding lead over his rival.
In Wisconsin on Saturday, Mr Kerry told a rally: "It was wrong to divert our forces from Afghanistan so that we could rush to war in Iraq without a plan to win the peace."
But later, perhaps mindful of Mr Bush's charges that he has made a "shameful" attempt to win votes from Bin Laden's threat, Mr Kerry insisted the country was "united as Americans.
"There is no Democrat, there is no Republican. We are all Americans and all united in our determination to seek out and destroy Osama Bin Laden," he told a rally in Iowa.
'Time of war'
At a rally in Florida on Saturday, Mr Bush reminded chanting supporters they were "going to the polls in a time of war and ongoing threats".
He promised to be "relentless, steadfast and determined" in combating those threats.
He joked that he was blunt, and sometimes "mangled the English language", but "you know where I stand and where I'm going to lead this nation".
Addressing fears that the ongoing conflict in Iraq could see a reintroduction of compulsory military service, Mr Bush there would be "no draft".