WASHINGTON — President Barack Obama is departing Thursday on a two-day bus tour of Ohio and Pennsylvania, offering a defense of his economic policies and his decision to rescue U.S. automakers while raising more questions about Republican Mitt Romney's business record.

Obama's 250-mile "Betting on America" bus tour is taking him through several northern Ohio communities where he received strong support in the 2008 election. The tour also will take him into western Pennsylvania with a stop in Pittsburgh.

Obama won both states four years ago, but Romney and Republicans are competing hard to win them. The president will campaign there as the nation's latest monthly job-creation assessment is released Friday. Each state had an unemployment rate of 7.3 percent in May, below the national average of 8.2 percent.

Four months before the election, polls show Obama slightly leading Romney nationally and in several states that are critical in the hunt to reach the 270 electoral votes needed to win the Nov. 6 election.

The bus tour starts a new phase of Obama's re-election campaign as he takes a more retail-oriented approach before the September convention in Charlotte, N.C. It follows a six-state bus trip by Romney through the Midwest last month that also included stops in Ohio and Pennsylvania. Recent polls by Quinnipiac University found that Obama held a 9-percentage-point lead over Romney in Ohio and a 6-point lead in Pennsylvania.

The president's itinerary takes him across the northern manufacturing belt of Ohio, which has felt the recession's sting perhaps more acutely than other parts of the state. It includes stops at a museum complex in Maumee that gives visitors a sense of life in the early 19th century; an ice cream social in a park in Sandusky; and an event at a park in Parma, a suburb of Cleveland. Friday's schedule includes a stop at an elementary school in Poland, Ohio, near Youngstown, followed by a speech at Carnegie Mellon University in Pittsburgh.

During the stop in Maumee, outside Toledo, Obama is expected to discuss an unfair trade complaint against China that his administration was to file Thursday with the World Trade Organization. The complaint centers on new Chinese duties on U.S.-made cars, including the Jeep Wrangler, which is made in Toledo, a senior administration official said. The U.S. believes the duties violate international trade rules, said the official, who requested anonymity in order to speak ahead of the president's announcement.

China has at times become a focal point in the presidential campaign. Romney has accused Obama of being too soft on China, while the Obama campaign has accused Romney of outsourcing jobs to China when he ran the private equity firm Bain Capital.

"Mitt Romney's companies were pioneers in outsourcing U.S. jobs to low-wage countries," says an Obama ad airing in Ohio, Pennsylvania and other states. "He supports tax breaks for companies that ship jobs overseas. President Obama believes in insourcing." The ad also highlights Obama's decision to rescue the U.S. automakers General Motors and Chrysler. Both companies have a large manufacturing footprint in Ohio.

Former Gov. Ted Strickland, D-Ohio, previewed the president's expected critique in a conference call organized by Obama's campaign, saying: "Romney literally made a fortune investing in companies that were pioneers in sending jobs to countries like China and India. Romney didn't bet on the American worker; he bet against them."

Romney's team countered that Obama has presided over a series of broken promises on unemployment, the economy and the federal deficit.

"No one should bet against America. But we certainly shouldn't double down on Barack Obama," said former Minnesota Gov. Tim Pawlenty, a top Romney surrogate. "We tried that and it ended up in a busted hand."

Republicans are dispatching Pawlenty and Louisiana Gov. Bobby Jindal, two potential vice presidential nominees, to some of the same towns along Obama's tour.

Ohio Republican Sen. Rob Portman, yet another potential Romney running mate, also had a column running in an Ohio newspaper Thursday accusing Obama of implementing policies that "make it harder, not easier, to create jobs here in Ohio and around the country."

The bus tour will coincide with Friday's release of the June jobs report. The May report showed unemployment had ticked up to 8.2 percent, while the economy created about 69,000 jobs, raising concerns among Obama's team about the potential for the economy to slow down. Earlier this week, economists reported that U.S. manufacturing shrank in June for the first time in nearly three years, adding to the questions about the economy.

Another bad report could undermine Obama's argument that the economy has shown signs of improvement and can rebound more fully if Republicans in Congress implement some of his ideas on job creation. An Associated Press-GfK poll released last month found that more than half of those surveyed, 52 percent, disapproved of his handling of unemployment, compared with 45 percent who approved.

The president's campaign had spent nearly $16 million in television advertising in Ohio through late June, while the Democratic super PAC Priorities USA Action had spent about $2.7 million, according to officials who track ad buys. Romney's campaign had spent about $5 million, but a series of GOP-leaning outside groups had spent another $8 million, helping the Republican blunt Obama's message.