U.S. Sen. Barack Obama's campaign lashed out Tuesday against a California-based political organization that is running negative ads against the Illinois senator.

Roger V. Salazar, a spokesman for the group American Leadership Project, denied allegations that the organization is affiliated with Obama's Democratic rival, U.S. Sen. Hillary Clinton.

The organization has purchased about $700,000 in Indiana media time to air its ads, which say Obama presents no specifics on fixing the state's economy and urge viewers to call his office.

Bob Bauer, chief counsel for the Obama campaign, told reporters Tuesday morning that the American Leadership Project was illegally gathering money for the attack ads and then failing to disclose its activities in campaign finance reports.

"This group is breaking the law and the people who are running it and funding it are going to be held accountable," Bauer said, comparing it to the Swiftboat Veterans for Truth organization that ran ads against Democratic presidential candidate John Kerry in 2004.

Public records show Salazar works for Sacramento political consulting firm Acosta Salazar, whose address is listed in the IRS paperwork that founded American Leadership Project. Records show Acosta Salazar's past customers include President Clinton, presidential candidate Al Gore and presidential candidate John Edwards.

Salazar flatly rejected Bauer's comments and said the organization took great pains to consult with attorneys on its legality.

"We are an issues-based political organization. ... We're not going to be bullied," Salazar said Tuesday of Bauer's comments.

Clinton spokesman Jonathan Swain said the campaign has no connection with the organization, nor any knowledge of its activities.

The organization is classified as a "Section 527" group because of the section of the IRS tax code that allows its creation. The groups can legally run politically based ads, as long as they do not work directly with any candidate or explicitly call for the defeat or election of any candidate.

Bauer said the Federal Election Commission issued millions of dollars in fines against 527's in the wake of illegal activity in the 2004 presidential race. He said the American Leadership Project was risking similar fines and possibly criminal sanctions.

Said Salazar: "We're been very careful with the set up of this organization. ... We're meeting all of the disclosure requirements."