U.S. Democratic presidential candidate Barack Obama widened his lead over opponent Hillary Clinton by winning the Wisconsin primary Tuesday.
Meanwhile, John McCain was steps closer to the Republican presidential candidacy after he swept the Wisconsin race.
With 56 percent to 43 percent in 60 percent of precincts counted, Illinois Senator Obama beat New York Senator Clinton in his consecutive ninth victory following Super Tuesday, when a full-scale race for the Democratic presidential nomination took place in 22 states and American Samoa.
"The change we seek is still months and away," Obama told supporters in Houston, Texas, whose delegate-rich primary is to take place on March 4.
"It is going to take more than big rallies. It is going to require more than rousing speeches," he said of the challenges ahead.
Clinton, who has moved on to the next battlefield in Ohio whose primary is also set for March 4, told supporters in the northeastern city of Youngstown that the presidential nomination race was aimed at "picking a president who relies not just on words, but on work, on hard work to get America back to work."
"They need a president ready on day one to be commander-in-chief, ready to manage our economy, and ready to beat the Republicans in November," she said.
However, CNN exit polls in Wisconsin showed that Obama beat Clinton in electability with 63 percent of voters saying he was most likely to win the national elections.
According to the polls, he also won the majority of votes at all different annual income levels, overturning earlier thinking that Clinton was more popular among blue-collar and rural voters in the state.
For voters who care about the economy, Iraq or healthcare, Obama was more capable of being the Democratic presidential candidate. He also sustained a lead among young, independent and educated voters, main components of his supporter base.
On the Republican side, Arizona Senator McCain maintained a two-digit lead over former Arkansas governor Mike Huckabee at 54 percent to 38 percent in 60 percent of precincts counted.
"I promise you I will wage a campaign with determination, passion, and the right ideas for strengthening our country that prove worthy of the honor and responsibility you have given me," the 71-year-old Vietnam veteran told a supporter rally.
Targeting Obama as a potential rival in the national elections, McCain also vowed to "make sure Americans are not deceived by an eloquent but empty call for change."
Exit polls showed McCain has improved his support among social conservative voters who are the Republican backbone, by winning 45percent of their votes in Wisconsin, compared to about 30 percent in Maryland primary.
McCain has so far accumulated over 900 delegates, taking him just steps away from winning the 1,191 needed to be the Republican presidential nominee in the national election.