Sarah Palin (photo), US Republican vice-presidential nominee, has accused Barack Obama, the Democratic candidate to the White House, of associating with terrorists.
She said the Illinois senator had been “palling around” with an ex-member of US-based militant group Weather Underground, which opposed the Vietnam War in the 1960s.
Mr Obama once served on a charity board with a member of the group, but he has denounced its activities.
“What’s clear is that John McCain and Sarah Palin would rather spend their time tearing down Barack Obama than laying out a plan to build up our economy”, said Hari Sevugan, a Democratic spokesman, who accused the Republicans of gutter politics.
Mrs Palin’s attack forms part of a broader Republican strategy to attack Mr Obama’s character, said commentators.
The time had come to take the gloves off, said Alaska Governor Palin, while speaking to supporters in Colorado and later in a Los Angeles suburb.
Quoting a New York Times article, she attacked Senator Obama over his link to Bill Ayers, a founder of the Weather Underground, which waged a violent campaign against the Vietnam War.
In the 1960s, the group was blamed for a number of bombings in the US.
Mrs Palin described senator Obama as someone who saw the US “as being so imperfect… he is palling around with terrorists who would target their own country”.
Several years ago, Mr Obama (photo) served on a charity with Mr Ayers, who is now a professor at the University of Illinois. Though he was a child when Weather Underground was active, the Democratic White House hopeful has denounced Mr Ayers’ radical past.
The Alaska governor also said she wished the McCain campaign had not pulled out of the battleground state of Michigan this week, which effectively conceded it to the Democrats.
In the same time, the healthcare plans of Republican presidential nominee John McCain was attacked by Mr Obama.
Speaking at a rally in Virginia, in front of 18 000 people, Mr Obama described the Arizona senator’s policy as “radical” and claimed 20 million people would be left out by it.
While senator McCain is in his home state preparing for Tuesday’s second presidential debate, one of his spokesman said that was “a bald-faced lie”.
As healthcare is important to voters, new adverts attacking Mr McCain on the issue have been unveiled by the Obama campaign in every battleground state.
Monday is a deadline for voters to register in Virginia, where Mr Obama held his rally, but also in more than a dozen other states, like Pennsylvania, Michigan, Ohio, Indiana and Florida.
Voter turnout could be vital in deciding the outcome of the 4 November presidential election.
In the same time, viewing figures show a record 69.9 million people tuned in to watch Mrs Palin take part in Thursday’s televised vice-presidential debate (photo, from cbc.ca) with Joe Biden, Mr Obama’s running-mate.