A new poll indicates U.S. President Barack Obama has a lead for the first time over Republican presidential front-runner Mitt Romney.

The ABC News-Washington Post survey indicates President Obama would beat Mr. Romney 52 to 43 percent in a hypothetical election matchup. The poll, conducted last week among a random sample of 1,000 adults, shows 50 percent of those surveyed approve of the president's job performance and believe he deserves a second term.

In a televised interview Sunday, President Obama said he deserves to be re-elected, citing new figures that indicate the economy is adding jobs. He told NBC the economy is doing much better than when he took office three years ago, but that, “we are not done.”

The president noted a report that said the unemployment rate fell in January for the fifth month in a row, with nearly 250,000 jobs added. In 2009, he said, the economy was losing three times that many jobs per month.

But the Republican presidential hopefuls say the economy is not recovering fast enough and Mr. Obama's policies have been ineffective.

The four Republican candidates are campaigning in Minnesota and Colorado, which holds its caucuses Tuesday.

Former Massachusetts governor Romney appears poised to win Colorado caucuses Tuesday. But polls in Minnesota suggest any one of four candidates could take first place, with former senator Rick Santorum in the lead.

Opinion surveys in both states show former House speaker Newt Gingrich has lost significant support.

Gingrich had been considered Romney's closest rival for the nomination, and in December held a commanding lead in Colorado polls. He is now in third place in that state.

Public Policy Polling, which conducted the latest surveys, says Santorum has been helped because no other candidates have been attacking him.

Romney has won the contests in New Hampshire, Florida, and Nevada. He is hoping to maintain his momentum with wins Tuesday in Colorado, Minnesota, and on Saturday in Maine.

But if Santorum can pull off a victory in Minnesota and a second place finish in Colorado, he may become Romney's biggest challenger for the nomination. Santorum is also polling well in Missouri, according to Public Policy Polling's latest survey there last week.

Gingrich is vowing to fight all the way to the nominating convention, being held in Tampa, Florida, in August.

Representative Ron Paul also remains in the race, but is trailing the other three candidates.