Mitt Romney plans to buy TV ads in California and other Super Tuesday states, contradicting earlier reports that he was avoiding a costly campaign on Feb. 5, when 21 states hold Republican primaries and caucuses.

As Romney seeks to topple John McCain's momentum coming out of his win in the Florida primary and a host of big-name endorsements, he said in Long Beach Thursday that he's authorized a seven-figure advertising buy.

He said that even though he can't flood the airwaves in every state, "given the number of states going at the same time, this is a time where our message to the main purveyors of information in the world is the best way for us to get our message out."

Romney's advisers had given him several options, ranging from spending $1 million for ads to $7 million. It was not immediately clear how much money Romney was willing to spend - or whether the multimillionaire would dip into his own bank account again. He already has poured at least $40 million into his presidential campaign.

The campaign will determine shortly which states it will target beyond California.

McCain aides said he, too, is preparing to run a high volume of commercials on national cable channels and in key states, but Romney will likely be the first GOP candidate on air in the Super Tuesday states, the broadest battleground of the primary season.

Romney's first ad in California, though, actually passed over McCain in favor of attacking Democrat Hillary Clinton, criticizing her for lacking experience.

But as the mega-contest looms, Romney and McCain clashed sharply at the Wednesday night debate in California, trading accusations on topics ranging from taxes to their positions on the Iraq war to conservative credentials.

Romney has been trying to cast himself as more conservative than McCain. He claimed the Arizona senator was outside the mainstream Wednesday night and even accused McCain of "dirty tricks" and old-style Washington politics for repeating a charge that Romney supports a timetable for troop withdrawal in Iraq. Romney insists that is not true.

The debate Wednesday night further defined the contest as a two-man race, but McCain is already leading in the polls in several delegate-rich Feb. 5 states, including California.

Mike Huckabee is also trying to stay competitive in the race. He and Ron Paul participated in Wednesday night's debate alongside Romney and McCain.

Romney had indicated on Wednesday that his campaign was not trying to purchase television advertising time in any of the states on the Super Tuesday calendar. Instead, his plans called for campaigning in California and other primary states, while making organizational efforts primarily for caucus states.

That still holds, though Romney now will supplement his campaigning with advertising.

His travel schedule reflects his campaign targets -- if not his advertising goals.

The campaign was planning to focus on areas with heavy concentrations of Romney's fellow Mormons: California, Arizona, and Utah, seat of The Church of Jesus Christ of Latter-day Saints.

Romney, trying to become the first Mormon president, will attend the funeral of the church President Gordon B. Hinckley on Saturday in Utah.

He also planned a stop Friday in Colorado, followed by visits to Minnesota, Illinois and Missouri, key Midwestern states. In Missouri, a classic swing state, Romney enjoys the strong support of Gov. Matt Blunt.

Also on the tentative schedule were Tennessee and Georgia, Southern states where Romney has shown strength. Romney was likely to bypass delegate-rich New York and New Jersey after former New York mayor Rudy Giuliani dropped out of the race and endorsed McCain.

Romney's home state of Massachusetts also votes Tuesday. His campaign tentatively planned to receive the Super Tuesday returns there, though a strong result was not assured.

In contrast to Romney, McCain plans to rely largely on momentum and the "free" news coverage that comes with it by holding rallies and news conferences in California and big winner-take-all delegate states, including New York and Illinois. McCain was picking up the endorsement of California Gov. Arnold Schwarzenegger on Thursday, an event sure to garner loads of publicity.

His aides say he would make a modest and targeted TV advertising push in some states.

With winner-take-all states his first priority, McCain's tentative travel schedule calls for him to travel coast to coast for general-election style rallies in Missouri, Illinois, Tennessee, Alabama, Georgia, Massachusetts, New Jersey and New York.

FOX News' Carl Cameron and The Associated Press contributed to this report.