Jan. 29, 2008 -- Washington lobbyists and members of Congress gathered at a popular Capitol Hill bar and restaurant last night to raise hundreds of thousands of dollars for GOP presidential candidate Sen. John McCain, whose staff refused to disclose exactly how much was raised or by whom.

"Like most campaigns, we do not release numbers of attendees or dollars raised per event," said McCain spokesperson B.J. Boling.

While McCain did not attend the event, a copy of the invitation obtained by ABCNews.com shows that donors who paid between $1,000 and $2,300 were invited to rub elbows with some of the 32 members of Congress supporting McCain for a reception at the Charlie Palmer Steakhouse. Donors who raised at least $10,000 were designated co-chairmen for the event and were treated to a "VIP Roundtable" before the main reception. The invitation lists 24 lobbyists as "co-chairman" for the event. The lobbyists represent a range of industries, including the finance, telecommunications, technology and healthcare sectors.

McCain has 59 lobbyists raising money for his campaign, more than any of the other presidential candidates, according to the latest finding from government watchdog group Public Citizen. The group, which advocates for public financing of elections, has identified more than 2,300 well-connected individuals, known as "bundlers," who have solicited contributions from friends and associates on behalf of a presidential candidate.

McCain is known as a champion of campaign finance reform. His campaign Web site touts the senator's credentials as a reformer, stating that he has fought for "greater transparency regarding the official activities of lobbyists" and the "disclosure of how candidates and campaigns are funded."

When it comes to disclosing how much lobbyists are raising for his presidential campaign, however, the group found that McCain has fallen short, even by standards set by the Bush/Cheney 2004 campaign which voluntarily disclosed on its Web site the names of bundlers who raised at least $100,000 and $200,000.

"As far as transparency goes, they all have to do better, including McCain," said Taylor Lincoln, who directs the project for Public Citizen. Lincoln says that Democratic Sens. Barack Obama and Hillary Clinton are the only presidential candidates who have disclosed the minimum amount their bundlers are raising.

"Everyone knows that John McCain is someone who has always stood on principle, taking stances against special interests," responded Boling when ABCNews.com asked whether the campaign would provide more disclosure. "Individuals who support John McCain do so because they believe he's the right man at the right time to lead as our next president. Our donations are fully disclosed with the FEC and we have a complete list of our finance committee on our Web site."

Click Here for the Investigative Homepage.