Ads in New York and elsewhere sponsored by the campaign of George W. Bush and his supporters are "the worst kind of American politics," John McCain said Friday.

Four days before the Republican primary in New York, McCain faced a barrage of attack ads in a key state that polls show is up for grabs. Republicans also will vote Tuesday in contests in California, Georgia, Ohio and nine other states.

McCain objected to one television ad in particular that is being aired by a previously unknown group called Republicans for Clean Air. The organization is spending $ 2 million --- according to records compiled by the McCain campaign --- in New York, Ohio and California to criticize McCain's record on the environment and praise Bush's.

"To have undisclosed a couple of million dollars coming into a campaign that's very close without knowing who's behind it and what it's all about is the worst kind of American politics. It just reinforces my zeal for campaign finance reform," McCain said.

His campaign tried to rebut the ad by bringing to New York the leader of a 5-year-old Republican group that has endorsed McCain. Martha Marks, a Lake County, Ill., commissioner and president of Republicans for Environmental Protection, said McCain's environmental record is far from sterling, but it is better than Bush's. "His environmental record in Texas is flat out lousy," Marks said.

The new organization running the anti-McCain ad is headed by Sam Wyly, a wealthy Dallas investor who with his brother, Charles Wyly, has given Bush more than $ 200,000 for his campaigns for governor in 1994 and 1998. Sam Wyly runs Maverick Capital Fund, an investment fund.

Bush denied any involvement with the ads Friday.

"I don't know who funded those ads," he said prior to being told that Wyly acknowledged heading Republicans for Clean Air.

"There is no connection between my campaign and this ad," he repeated. "We had no knowledge whatsoever that Sam Wyly was going to run this ad."

Bush also is attacking McCain on the health care front, mounting a radio ad in New York that criticizes the Arizona senator for failing to support federal funding that includes breast cancer research. In the ad, breast cancer survivor and activist Geri Barish noted that McCain opposes local cancer research programs as "garden-variety pork." The projects were contained in a military spending bill, which McCain said he opposed because it contained insufficient salary increases for U.S. soldiers.

"That's shocking," Barish says on the ad. "America deserves better. Next Tuesday, John McCain won't have my vote."

McCain, whose sister, Sandy McCain Morgan, was diagnosed with breast cancer two years ago, said he has many times voted to fund cancer research projects.

"It's not the way that I would campaign and it's not true and everybody knows it's not true," McCain said.

Bush said he sees nothing wrong with the ad.

''I don't think the senator should be squealing about pork and then squealing when somebody disagrees with one of the cuts he wants to make. That's what the ad says,'' Bush added.

Told of the illness suffered by McCain's sister, Bush said: ''All the more reason to remind him of what he said about the research that goes on here. I'm sorry if that's the case; that obviously is very difficult for her and her family.''

Cox news reporter Ken Herman contributed to this article.