CHICAGO -- Strategists for the Democratic presidential campaigns of Sens. Barack Obama and Hillary Rodham Clinton exchanged calculated barbs yesterday over accountability and ethics and who is engaging in personal attacks.

Obama communications director Robert Gibbs called on Mrs. 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?" Mr. 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 Mrs. Clinton's strength in Pennsylvania.

Mr. Obama was heading for Pennsylvania today to campaign, with stops later in the week likely in North Carolina and Oregon. Mrs. Clinton prepared to give a speech on the Iraq war today in Washington, D.C.

The Obama campaign's move on Mrs. 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, Mr. Obama disavowed racially tinged comments by the Rev. Jeremiah Wright, who was Mr. Obama's pastor for nearly 20 years before retiring recently.

Mr. 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.

Mr. Obama's team asserted that Mrs. Clinton was continuing to shield financial documents from public scrutiny at the same time when she was calling for greater accountability.

The New York senator has said she will release tax returns for the years after 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 Mr. 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," Mr. Axelrod said, noting that Mr. Obama would be there today and tomorrow.

Still, said Mr. Axelrod, "[Mrs. 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."