BOSTON — GOP presidential candidate Mitt Romney won Utah and five other states in early results in Super Tuesday voting, but that wasn't enough to keep him from falling even further behind the party's front-runner, Arizona Sen. John McCain.

Still, Romney said he wasn't ready to quit the race when he addressed supporters gathered at the Boston Convention and Exhibition Center for what his campaign had billed as a victory party.

"I think there are some people who thought it was all going to be done tonight. But it is not all done tonight. We are going to keep on battling," Romney said. "We are going to go all the way to convention.

We are going to win this thing, and we are going to go to the White House."

In addition to Utah, where he had led the 2002 Winter Olympics in Salt Lake City, Romney was also expected to win his home state of Massachusetts and Colorado, Montana, Minnesota and North Dakota.

McCain was projected to win California, Arizona, Connecticut, Illinois, New Jersey, New York, Delaware, Oklahoma and Missouri. Those victories helped boost McCain's overall delegate count to more than twice the size of Romney's.

McCain told his supporters at a gathering in Arizona Tuesday night that "we still have a ways to go, but we are much closer to the victory we have worked so hard to achieve. I am confident we will get there."

McCain's California win could speed the end of Romney's bid for the White House. Romney's supporters had said he needed a strong showing among California conservatives to continue in the race.

But based on exit polls, CNN projected McCain as the winner in California late Tuesday. With 17 percent of the state's precincts reporting, McCain had 44 percent of the vote compared to 25 percent for Romney.

Even former Arkansas Gov. Mike Huckabee, a Southern Baptist minister, had a surprisingly strong showing Tuesday with an early victory in West Virginia's delegate convention, and in Arkansas, Alabama, Georgia and Tennessee.

Romney had been pressuring Huckabee to drop out of the race, suggesting he was a spoiler. His campaign manager, Beth Myers, suggested in a statement that McCain had "cut a Washington backroom deal" with Huckabee that hurt conservative Republicans.

"Unfortunately, this is what Sen. McCain's inside Washington ways look like: He cut a backroom deal with the tax-and-spend candidate he thought could best stop Gov. Romney's campaign of conservative change," Myers said.