Four South Carolina polls released Wednesday show former House Speaker Newt Gingrich in a virtual dead heat with frontrunner Mitt Romney.

Each candidate leads two of the polls. With Texas Gov. Rick Perry dropping out of the race, Gingrich could pick up even more voters with the primary just three days away.

Romney's largest lead came in an NBC/Marist poll in which he earned 34 percent support among likely primary voters. Gingrich earned 24 percent.

Romney also led the Politico/Tarrance poll, earning 37 percent support to Gingrich's 30 percent.

But in the InsiderAdvantage poll, Gingrich overcame an 11-point deficit to regain the lead. He earned 32 percent support in the poll, while Romney earned 29 percent support.

And in the Rasmussen poll, Gingrich leads Romney 33 percent to 31 percent. Just two days ago, Romney led the same poll by 14 points.

Gingrich also leads a modified Public Policy poll released Thursday, with 34 percent support. PPP planned to release the full results after more polling on Thursday, but released tracking results when Perry dropped out.

During the past week, support for Gingrich and Romney has been on the rise, while support for all of the other candidates has dipped.

In the NBC poll, Rep. Ron Paul and Sen. Rick Santorum earned their highest levels of support, with 16 and 14 percent respectively.

Gov. Rick Perry failed to earn more than 4 percent support in any of the polls.

According to the RealClearPolitics average, Romney still holds a 7-point lead on Gingrich, but Perry's departure and Thursday's debate could change that.

Another poll, from Public Policy Polling, is expected out Thursday evening.