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ABC News' Michael Falcone reports:

Mitt Romney accused Rick Santorum's presidential campaign of being "in league" with Democrats who are trying to undermine his chances of winning the Michigan primary by encouraging cross-over votes for Santorum.

In a pre-taped interview with Neil Cauvto set to air tonight at 6 p.m. on Fox Business Network, Romney said: "There is no question they are in league; they probably haven't communicated with one another, but they don't need to."

"That tells Republicans who the Democrats are most afraid of and it's not Rick Santorum it's me and that's why they are doing that," he added.

Romney, who predicted less than 24 hours ago that "I'm going to win in Michigan" changed his tune in tonight's interview to "I would like to win in Michigan."

"I will pick up a lot of delegates in Michigan, whether I win or not," he said.

He also predicted that he would end up with "two or three times as many delegates coming out of tonight as anybody else," according to early excerpts of the Fox interview.

Santorum, who is locked in a tight race with Mitt Romney in the state, has paid for robo-calls inviting Democrats to cross-over and vote for him. The call began hitting Michigan households on Monday. "On Tuesday join Democrats who are going to send a loud message to Massachusetts Mitt Romney by voting for Rick Santorum for president," an announcer says.

ABC News has also learned of a   another robo-call, sponsored by a Democratic political consultant, that will go out at 5 p.m. on Tuesday reminding voters that they only  have three hours left to vote for the Republican candidate. "Of course," the caller says, "you want to vote for Rick Santorum."

As far as the prospect of a brokered convention goes, Romney isn't buying it.

"The four of us would have to find a way to make it work amongst ourselves because we are not going to hand this off to someone else after all the work we have done," he said.

And Romney denied rumors that he and fellow candidate Ron Paul are working together in the primary race.

"No of course not," Romney said of the chatter about coordination between the two campaigns. "No one is going to tell Ron Paul what to say. We like each other. We don't know each other extensively, but we get along just fine."