Former U.S. congressman Newt Gingrich has won the Republican presidential primary in the southeastern state of South Carolina, shaking up the party's campaign to find a candidate for this year's presidential election.

With more than 95 percent of the precincts reporting, vote tallies showed Gingrich with about 40 percent of the vote. Former Massachusetts governor Mitt Romney trailed in second with about 28 percent.

Gingrich touted his victory with an apparent jab at Romney, who has faced criticism from his rivals over his wealth.

“We don't have the kind of money at least one of the candidates has. But we do have ideas, and we do have people. And we proved here in South Carolina that people power with the right ideas beats big money, and with your help, we are going to prove it again in Florida.”

Just a week ago, Romney was expected to win easily, but his campaign was hard hit by attacks over his career as a venture capitalist.

After the initial results emerged Saturday, Romney hit back, criticizing both President Barack Obama and Romney's Republican rivals.

“Our president has divided the nation, engaged in class warfare, and attacked the free enterprise system that has made America the economic envy of the world. We cannot defeat that president with a candidate who has joined in that very assault on free enterprise. (applause). When my opponents attack success and free enterprise, they are not only attacking me, they are attacking every person who dreams of a better future.”

In third in the South Carolina vote was former U.S. senator from Pennsylvania, Rick Santorum, with U.S. Congressman Ron Paul of Texas in fourth.

Paul said he expects to end up with four to five times more votes in South Carolina this year than in the 2008 race. He said his cause of liberty is getting more attention now because of current conditions.

“Well the evidence has become clear that the efforts by government are failing, and we can't depend on the government to take care of us from cradle to grave, we can't depend on the government, on its efforts to promote, and to believe that we can police the world, and go in and nation-build, because we're all going broke.”

Gingrich's upset victory means that all three of the election events held so far have had different winners. Romney won the New Hampshire primary last week, and Santorum won the Iowa caucuses on January 3.

Santorum made note of the volatility in his speech Saturday night.

“Well, three states, three winners, what a great country!”

The battle will continue to be hard fought in the next primary state – Florida. Republicans there will vote on January 31.