PORTLAND, Maine - Seeking support in Northeast primary states, John McCain urged voters Saturday to reject attempts by "two Texas cronies of George W. Bush to hijack an election" with $ 2.5 million in new anti-McCain television ads.

"Tell 'em to keep their dirty money in the state of Texas, my friends," Mr. McCain told a crowd at Copley Square in Boston. "Don't spread it all over New England and America."

Mr. Bush on Saturday continued to deny any link to the ads, an assertion that Mr. McCain and his aides have questioned.

Dallas investor Sam Wyly, whose brother Charles is a top fund-raiser for the Bush presidential campaign, financed the TV spots, which praise the Texas governor and condemn Mr. McCain on the environment.

The bickering dominated the Republican rivals' stumping on the weekend before the biggest voting day of the primary season. Contests in 16 states from coast to coast could settle the race Tuesday.

Mr. Bush said his campaign didn't know Mr. Wyly had funded the ad until a reporter asked about it. He said the Dallas billionaire had the right to air the spot.

"In politics people have the right of freedom of speech, the right to spend money the way they spent it," Mr. Bush said.

Mr. McCain said the ads justify his major campaign theme, the need for campaign finance reform. The Arizona senator wants to ban the "soft money" that political parties and independent groups can use in an unrestricted manner.

"In the last couple of days we have seen the worst examples of the need for campaign finance reform," Mr. McCain said. "Two cronies - two cronies - of Governor Bush got together two and a half million dollars [and] spent it on attack ads that are being run all over America, attacking me on environmental issues."

"This is the best argument for campaign finance reform. They have made my case. I rest my case."

Mr. McCain is a strong favorite in Massachusetts and Maine, but the New York race is considered a dead heat. Given the polls that show him far behind among Republicans in California and Ohio, New York is probably Mr. McCain's best chance to score a breakthrough win, aides said.

For his part, Mr. Bush sought to steer the political debate to education.

"This man is running for president, he's not running for legislature," said Mr. Bush. "He's running for the chief executive of the country. And a chief executive must be able to lay out a comprehensive vision how to work with local jurisdictions on how to demand accountability."

On Saturday, the Bush campaign began airing a new radio commercial in New York saying Mr. McCain does not have an education agenda in the presidential race.

The ad says that during last Thursday's GOP debate, Mr. McCain couldn't list a significant education achievement as senator.

"If John McCain has never made education a priority as senator, why would he as president?" an announcer asks in the Bush ad.

Although not addressing the allegations directly, Mr. McCain talked at length about education during a speech late Saturday at a Vietnam veterans memorial park in Rochester, N.Y.

He called for teacher merit pay based on student performance, encouragement of charter schools that would be independent of local school boards and experiments with the voucher program financed with cuts in "corporate welfare" rather than existing education funds.

Mr. Bush picked up an endorsement from a fellow high-profile state leader: New Jersey Gov. Christie Todd Whitman.

"As a Republican, I endorse him because we share a conservative Republican philosophy that transcends litmus tests," she said.

Ms. Whitman supports abortion rights, a contrast to Mr. Bush's stance.

Also Saturday, Mr. Bush scrapped a planned interview for Sunday's 60 Minutes after Mr. McCain was offered equal time.

Bush campaign spokeswoman Karen Hughes said the governor thought the interview was "a good opportunity to speak to a lot of people" before Tuesday's voting. But giving his rival a segment "changed the nature of the interview request," so Mr. Bush pulled out.

"It's unfortunate that Governor Bush would rather wage his campaign with negative advertisements and false accusations and hide behind negative attacks by his Texas cronies than participate in the most widely watched national news program with John McCain," said McCain spokesman Howard Opinsky.

Mr. Bush also participated in an early St. Patrick's parade in Binghamton, N.Y., where several thousand people lined the route through downtown.

Mr. McCain also received an endorsement, from The New York Times in Sunday's editions.

Staff writer Wayne Slater traveling with the Bush campaign and The Associated Press contributed to this report.