John McCain is straining to keep up with his own conflict-of-interest policy as Barack Obama's campaign took fresh shots at the Republican Thursday for retaining advisers who are part of an independent group attacking the Democratic front-runner.

Two top McCain surrogates -- Connecticut Sen. Joe Lieberman and South Carolina Sen. Lindsey Graham -- stepped down Wednesday from their positions on the policy board of advisers for the group Vets for Freedom, in their words, to comply with McCain's "campaign guidelines."

Those newly released guidelines prohibit anyone with a campaign title from working with a "527″ or other independent group that publicly supports or opposes a presidential candidate.

The New York Times reported Thursday that two Vets for Freedom members, Max Boot and Wade Zirkle, are still connected to the McCain campaign.

"It's not surprising to learn that Senator McCain, who waited nearly 15 months to produce a conflicts policy that his own staff admitted was developed just to deal with a 'perception problem,' is now not enforcing that policy," Obama spokesman Hari Sevugan said in a statement. "But it does beg the question of whether he's ready to change the way Washington works if he's not even ready to enforce his own rules to change the way his campaign works."

Vets for Freedom released a recent pair of Web videos sharply critical of Obama for not visiting Iraq since January 2006.

The videos feature Iraq veterans, whom McCain seemed to echo in talking points over the last couple days when he challenged Obama to travel to Iraq with him before dismissing the Bush administration's military efforts in the region.

"(Obama is) unwilling to get the facts on Iraq, yet he's willing to travel to Iran to meet with their leader or anyone else who hates our country," Sgt. Garrett Anderson says in one of the ads.

"The surge worked. But Barack Obama wouldn't know that. Because he hasn't been there in over two years," combat medic Kate Norley says in the other.

Obama says he's now considering a solo trip to Iraq. But with reports that the independent entity criticizing him on his travel was loosely tied to McCain himself, the Obama camp is trying to drive home the point that McCain is not as squeaky clean as he claims when it comes to ethics.

McCain's latest conflict-of-interest policy was released after adviser Craig Shirley stepped down following revelations that he was behind an independent group that had been criticizing Hillary Clinton and Obama on the Internet.

Under the new policy, nobody on the campaign can be a registered lobbyist or foreign agent, or receive payment for such work. The campaign required all staff members to disclose any lobbying ties, especially those that could be "embarrassing for the senator and the campaign."

The latest casualty was former Texas Rep. Thomas G. Loeffler, McCain's national finance co-chairman. Loeffler runs the lobbying shop The Loeffler Group, and his resignation in mid-May was the highest profile departure from McCain's inner circle since a summer 2007 shake-up cost McCain his campaign manager and chief strategist.

Several top strategists working on his campaign are lobbyists who have taken leaves of absence from their jobs to work for McCain. Among them are campaign manager Rick Davis and Charlie Black, a high profile Washington lobbyist with domestic and foreign clients.

Obama strategist David Axelrod was criticized in a recent Newsweek story for working with a consulting firm behind a group that basically lobbied on behalf of an Illinois utility company -- but in a Huffington Post interview Wednesday he maintained that he "never lobbied anybody" and tagged Black "the most powerful corporate lobbyist in Washington."

As he tries to weed out lobbying influence in his campaign, McCain is putting equal attention on ties to 527's -- groups like Swift Boat Veterans for Truth that attacked John Kerry in 2004 -- and other independent groups.

Vets for Freedom is a non-profit 501(c)(4), and the political action committee for the group released the ads on Obama.

Pete Hegseth, executive director of Vets for Freedom, told FOXNews.com that his group has no relationship with the McCain campaign.

He said the organization has not endorsed any candidate in the presidential race, and that the ads were "not an attack" on Obama.

"He's been one of our strongest allies," Hegseth said of the Arizona senator. "But as far as the ads ... there was absolutely no coordination with McCain."

Josh Grodin, government affairs director for Vets for Freedom, said the group was just raising a critical issue that will confront the next president.

"If this is going to be the commander in chief, these questions need to be asked," he told FOXNews.com.

McCain has been to Iraq eight times.

The Arizona senator said Thursday at a stop in Wisconsin that Obama still needs to follow through and visit the country, since he's "wrong" to want to set a timetable for troop withdrawal.

"Senator Obama, because I raised it, says now he is quote 'considering' going," McCain said. "I said I would go with him. He doesn't want to do that. That's okay ... but the point is that he needs to go and he needs to go soon."

Members of Vets for Freedom were partially placated by Obama's claim that he is considering a trip to Iraq.

"The proof is in the pudding," Norley said in an interview with FOX News. "As soon as he's over there, then I'll feel more confident about his statement."

Meanwhile, Obama, who declares his campaign is free from the contributions or direct influence of federal lobbyists, has had ethical problems of his own.

The Washington Post reported Thursday that the co-director of Obama's Puerto Rico campaign is a D.C.-based federal lobbyist for the Puerto Rico government -- a situation watchdogs said appeared to contradict Obama's own guidelines with lobbyists.

An Obama spokesman, though, told the Post that Francisco J. Pavía is just a volunteer, and so his work does not contradict campaign rules.

Obama's lobbyist guidelines are carefully tailored. The Illinois senator does accept contributions from state and local lobbyists.

FOX News' James Rosen and Judson Berger and The Associated Press contributed to this report.