Washington, Oct 26 (IANS): Amid seesawing polls and with just 12 days to go before the Nov 6 election, President Barack Obama and Republican challenger Mitt Romney are crisscrossing battleground states to swing voters their way.

Continuing on a non-stop two-day tour of several battleground states, Obama Thursday moved from Nevada overnight to Florida to Virginia, Illinois - where he voted in his Chicago hometown - and on to Ohio where he held a rally complete with the most presidential of backdrops - Air Force One.

Addressing about 12,000 supporters on the tarmac in Cleveland, Obama on his second trip to the swing state this week said: "I need you Ohio, America needs you Ohio."

At each stop, Obama has brought a blunt, boiled-down assessment of his Republican rival - Romney is not to be trusted - as he attacked Romney for rhetorically moving to the centre late in the campaign, according to the Los Angeles Times.

Underlining the importance of what is known as the "Buckeye State" on the path to 270 electoral votes needed to win the White House, Romney took a leaf out of Obama's 2008 campaign as he spent the whole day in the state telling voters that he was the candidate of "big change" while his rival was the candidate of the "status quo".

At his first of three rallies on his Ohio bus tour, Romney mentioned the phrase "big change" no less than a dozen times and argued that Obama had taken the country backward with his economic policies, the Times said.

He listed the nation's current challenges: underperforming schools, the debt and joblessness.

The rivals swing through the battleground states came as new polls of likely voters in two battleground states released Thursday showed Obama with a slight advantage in Nevada but tied with Romney in Colorado.

The NBC News/Wall Street Journal/Marist polls were conducted Tuesday and Wednesday - entirely after Monday's third and final presidential debate. In Colorado, the race is tied at 48 percent for each candidate, while in Nevada voters split 50 percent for Obama and 47 percent for Romney.

Meanwhile, FiveThirtyEight, an influential poll watching blog on the New York Times suggested the momentum of Romney, who clearly gained ground in the polls in the week or two after the Oct 3 first debate in Denver, seems to have stopped.

In eight national tracking polls, for instance, Romney gained ground in just one of the polls, an online poll conducted for Reuters by the polling organization Ipsos, it noted.

He lost ground in five others, with Obama improving his standing instead in those surveys. On average, Obama gained about one point between the eight polls.

While FiveThirtyEight Thursday raised Obama's likely share of electoral votes to 290.8 from 289.7 Wednesday, RealClearPolitics, another election news aggregating site, moved 15 electoral votes from Romney's column to toss-ups to give Obama a 201-191 advantage over Romney with 146 too close to call.