Rick Santorum has won the Alabama and Mississippi GOP presidential primaries, news outlets report.

With nearly 97 percent of Alabama precincts reporting Tuesday night, Santorum led Newt Gingrich with 34.5 percent of the vote to Gingrich's 29.3 percent, the New York Times reported. Mitt Romney followed in third place with 29 percent, and Ron Paul finished in fourth place with five percent.

In Mississippi, with 99 percent of votes tallied, the New York Times reported that Santorum led with 32.9 percent of the vote, while Gingrich followed with 31.3 percent, Romney trailed both with 30.3 percent support, and Ron Paul finished last with 4.4 percent support.

In Alabama, exit polls suggest Santorum did well with very conservative voters and women, CBS News reported.

Santorum's victories dealt a serious blow to front-runner Mitt Romney's campaign, and it raised questions about Romney's ability to unite the Republican party in the run-up to the GOP convention in Arizona in August. Santorum's claim that he is the official conservative alternative to Romney -- the candidate with the most delegates so far -- was furthered by his victories in the two Deep South states.

Newt Gingrich, the former House speaker, has only won two primaries so far: South Carolina and Georgia, the Wall Street Journal reported. Although he vows to keep on fighting in the election, his campaign now seems in question.

According the New York Times, Santorum defeated his rivals although he was outspent by Romney and was not as locally well-known as Gingrich in the two Southern states.

Alabama was the biggest prize for the evening, with 54 delegates at stake.

The Wall Street Journal reported that although Romney came in third in Alabama and Mississippi, he will claim roughtly one-third of the available delegates. Despite his defeat in Alabama and Mississippi, political experts predict Romney will win Hawaii and American Samoa, which both voted Tuesday, and whose results will be known Wednesday morning.