RICHMOND -- Republican Ken Cuccinelli and Democrat Terry McAuliffe on Thursday used a public forum on transparency in politics to discredit each others' gubernatorial campaigns as ethically suspect.

The two candidates for Virginia governor made separate appearances at the annual event sponsored by the Virginia Public Access Project, sharing the stage only briefly for a photo op. It was the first joint appearance by the pair since Cuccinelli was officially named the Republican nominee earlier this month, and both took advantage of the opportunity to take potshots at each other.

Cuccinelli, touting his own public transparency, renewed his challenge for McAuliffe to debate him in every corner of the state, as many as 15 debates. McAuliffe agreed to five, the traditional number of gubernatorial debates.

"I believe this is the fifth time in my life I've been in the same room with Terry McAuliffe, and of course, none of those were debates," said Cuccinelli. "It's not a gimmick. It's not a trick. It's important."

Cuccinelli, who made public eight years' worth of income tax returns, again called on McAuliffe to do the same. McAuliffe, a millionaire businessman and Democratic fundraiser, released summaries of his returns for three years but so far declined to release more.

McAuliffe responded with claims that Cuccinelli isn't as open and transparent as he claims, noting that the attorney general failed for years to publicly disclose gifts he received from Star Scientific CEO Jonnie Williams at a time when the company was suing the state over unpaid taxes.

"He didn't fill out the forms that he was required to do by law," said McAuliffe. "So before you come back and ask me [to release my tax returns], he did not do what he was required to do by law."

Cuccinelli said after the event that he would participate in the five debates McAuliffe agreed to but called it "inadequate."

"There are differences between us that are going to be the basis for people to make choices," said Cuccinelli. "And the way the electorate works, the lower turnout elections ... you really need to have [debates] in their locality, somewhere in the region, for the average voter to see it."

While Cuccinelli spent most of his time accusing McAuliffe of being the least transparent candidate in the race, the former Democratic National Committee chairman largely focused on the tenants of his campaign. During his 12-minute remarks, McAuliffe reiterated his support of the state's new tax hike to fund transportation, spoke of his plan to increase pre-K funding and promised to accept the Medicaid expansion under President Obama's health care reforms.

McAuliffe did, however, leave with a final shot at Cuccinelli, portraying his opponent as an extremist on social issues like abortion.

"We cannot grow our economy with a social ideological agenda when 50 percent of the workforce in the United States of America are women," McAuliffe said.