Romney, the likely GOP presidential nominee, said Obama is "a president who by his own measure has failed, and so he looks around for someone to blame," The Washington Post reported.
Speaking at the South Park Township, Pa., headquarters of Consol Energy, a coal and natural gas company, Romney tried to place responsibility for the country's sluggish recovery at Obama's feet.
"So he's out of ideas, and he's out of excuses, and in 2012, we've got to make sure he's out of office," Romney said.
Pennsylvania, Rhode Island, New York, Connecticut and Vermont conduct their party primaries Tuesday. They are the first primaries since former U.S. Sen. Rick Santorum of Pennsylvania dropped out of the race April 10 as polls showed Romney picking up steam in Santorum's home state.
Romney's pre-primary stump came as the former Massachusetts governor began rolling out his general election arguments and solidifying support en route to the Republican National Convention in Tampa, Fla., in August and his likely nomination as the GOP presidential candidate.
While Romney faces no serious challenge from former House Speaker Newt Gingrich or Rep. Ron Paul of Texas in Tuesday's contests -- the remaining major candidates -- he reminded supporters to vote Tuesday and work for him during the summer to convince friends "we need to have a president who understands the economy, who knows how to lead because he's actually led before, who'll go to work creating good jobs for the American people and will also go to work to make sure that the promise of America is kept."
Romney also said Obama has promoted wind and solar energy while his administration impedes development of fossil fuels, such as the coal and natural gas interests developed by Consol, the Pittsburgh Post-Gazette reported. Romney frequently disparages Obama as being unfriendly to the coal industry.
Democratic campaign staffers responded Romney, as governor, embraced rules against coal plant emissions similar to those he now criticizes.