Independent campaign spending is surging ahead of Super Tuesday.
Outside groups, including super PACs, have spent nearly $11.5 million through midday Monday on television ads, automated calls and other campaign activity in the 10 states that vote Tuesday, a USA analysis of Federal Election Commission records show.
No state is getting more attention than Ohio, where outside groups have spent $5.5 million. Polls show Republican presidential candidates Mitt Romney and Rick Santorum locked in the tight battle for Ohio -- a key battleground in November's general election.
Outside groups also spent heavily in Tennessee ($2.3 million) and Georgia ($2.2 million).
Restore Our Future, a super PAC supporting Romney, has spent the most -- $6.2 million -- in Super Tuesday states, including nearly $3 million in Ohio.
Winning Our Future, a pro-Newt Gingrich super PAC, was the second biggest spender, pumping nearly $3.3 million into the states that vote Tuesday. Its heaviest spending was in Gingrich's home state of Georgia, which he has declared a must-win state to remain a credible contender.