Sen. Barack Obama’s (Ill.) campaign posted the Illinois senator’s 2005-2006 full tax returns on its website Tuesday, urging Democratic rival Sen. Hillary Rodham Clinton (N.Y.) to follow suit and not wait until right before the Pennsylvania primary.

The Clinton campaign said Monday that it is planning to release the senator's tax returns shortly before the April 22 Pennsylvania primary, right after the April 15 filing deadline.

Obama’s campaign argued again Tuesday that Clinton’s tax returns are necessary for voters to see answers to a number of questions about her finances, specifically the origin of a $5 million loan she gave her campaign around the time her husband, former President Bill Clinton, received a $20 million payout from Yucaipa, “a supermarket holding company that invests in tax shelters in the Cayman Islands.”

“Sen. Clinton recently claimed that she’s ‘the most transparent figure in public life,’ yet she’s dragging her feet in releasing something as basic as her annual tax returns,” Gibbs said in a statement. “Sen. Clinton can’t claim to be vetted until she allows the public the opportunity to see her finances — particularly with respect to any investment in tax shelters.”