CLIFTON, Va. — President Obama barnstormed through this swing state on Saturday as his campaign relentlessly hammered at Mitt Romney’s business record, releasing a mocking new ad that shows Mr. Romney singing “America the Beautiful” as it accuses his former firm of shipping American jobs overseas.

Mr. Obama, speaking first to a drenched crowd during a downpour in the Richmond suburb of Glen Allen, and then at Centreville High School in Fairfax County, accused Mr. Romney of investing in “companies that have been called pioneers in outsourcing.” He ignored Mr. Romney’s demands for an apology about the campaign’s tone, which the Republican candidate had called for in interviews on Friday.

“My opponent and his allies in Congress, they believe in top-down economics,” Mr. Obama said. “If you cut through all the stuff, what they are really saying is tax cuts for the wealthy, roll back regulations. That is essentially their plan.”

The president’s campaign has spent more than a week harping on Mr. Romney’s personal wealth and calling on him to disclose information about his personal finances by releasing more years of his tax returns. It has also raised questions about Mr. Romney’s offshore investments and accounts.