Obama communications director Robert Gibbs called on Clinton to release full post-White House tax returns; disclose all congressional "earmarks," or pet projects she had inserted into spending bills; and release all documents on the Clinton Foundation and Clinton Library, including a list of donors.
"What is lurking in those documents?" Gibbs asked as the two campaigns had dueling phone conference calls with reporters. "There are gaps that need to be filled," said senior Obama strategist David Axelrod.
"This is a tried and true technique of the Obama campaign that has repeatedly shifted negative when they find the momentum working against them," said senior Clinton strategist Mark Penn. He suggested the Obama campaign was trying to "deflect public opinion from their losses in Ohio and Texas" and faced with Clinton strength in Pennsylvania.
The Obama campaign's move on Clinton came after a weekend in which the Illinois Democrat sought to ease public concerns about his ties to an indicted Chicago developer and to inflammatory statements by his former pastor.
In interviews with Chicago newspapers, a TV appearance and a Saturday speech in Indiana, Obama disavowed racially tinged comments by Rev. Jeremiah Wright, who was Obama's pastor for nearly 20 years before retiring recently.
Obama also worked to distance himself from Antoin "Tony" Rezko, a former fundraiser for the candidate who is currently on trial in Chicago on corruption charges.
Obama's team asserted that Clinton was continuing to shield financial documents from public scrutiny at the same time she was calling for greater accountability.
Clinton has said she will release tax returns for the years after her the end of her husband's presidency before the April 22 primary in Pennsylvania.
When asked if the request for tax information is what they are calling personal attacks, Clinton spokesman Howard Wolfson said: "When you accuse somebody of being disingenuous and question their integrity and their honesty, as they are doing, that constitutes a personal attack."
As to Pennsylvania, Obama strategist Axelrod rejected a suggestion that their campaign was all but giving up on the state and focusing its energies on primaries that come later where they expect to do better.
"'We are going to contest vigorously in Pennsylvania," Axelrod said, noting that Obama would be there on Monday and Tuesday.
Still, said Axelrod, "she (Clinton) does have a lot of advantages there - and we understand that. We know we have an uphill fight there. ... But in no way are we giving up on Pennsylvania."