Romney: Santorum's Robocall 'Dirty Trick'

Republican presidential candidate Mitt Romney is accusing his main rival, Rick Santorum, of pulling a "dirty trick" by sponsoring a computerized phone call urging Michigan Democrats to vote against Romney in Tuesday's Republican primary.

Santorum is shrugging off the criticism, telling Fox News that he is trying to attract the Democratic voters he'll need in a general election campaign.

The "robocall" going around Monday says Democrats should send "a loud message" to Romney by voting for Santorum. The message says it's supported by "hard-working Democratic men and women" and paid for by the Santorum campaign.

Romney tells Fox News that the robocall sounds like it's coming from organized labor, and he says the effort is confusing people and deceptive. Romney calls it "a new low" in the campaign.