ABC News' Michael Falcone and Elicia Dover report:

CHARLESTON, S.C. - Rising in the polls with just hours to go before voters begin casting their ballots in South Carolina, Newt Gingrich is under assault from shadowy forces trying to blunt his appeal in the Palmetto State.

Unknown opponents of Gingrich spent Friday - the last full day of campaigning before the primary - employing a variety of dirty tricks  against him beginning with a fake CNN e-mail news alert that read: "A source close to Marianne Gingrich tells CNN that former House Speaker Newt Gingrich forced her to abort a pregnancy conceived during the affair that preceded her marriage to Gingrich."

The e-mail message, according to a CNN report, had the appearance of one of the cable network's actual news alerts and showed the sender's address as: BreakingNews@mail.cnn.com

The mock news alert was followed by a fake press release made to look like it was sent by Gingrich's campaign responding to the doctored CNN message.

Under the dateline, "Orangeburg, SC" - the location of one of Gingrich's Friday campaign stops - the faux release began: "Newt Gingrich released the following statement regarding reports that he forced ex-wife Marianne Gingrich to terminate a pregnancy"

It looks very similar to the actual press releases the Gingrich campaign sends out on a daily basis, including the campaign logo and typefaces. It also includes the name and e-mail address for Gingrich's press secretary, R.C. Hammond.

It includes a fake quote from Gingrich: "I am not proud of some decisions I have made or actions I have taken, but I believe in the power of redemption and I trust the voters of South Carolina do as well."

A Republican source in South Carolina has passed along a copy of that message to ABC News.

Gingrich's relationship with his ex-wife became the instant focal point of Thursday night's Republican presidential debate in Charleston.

In the opening question, CNN moderator John King invited Gingrich to respond to an ABC News interview with Marianne Gingrich, the former House Speaker's second wife, in which she accused her ex-husband of demanding an open marriage so that he could have an affair with his current wife, Callista.

Here is a copy of the fake release:

FakeGingrichPressRelease.1.20 // <![CDATA[ (function() { var scribd = document.createElement("script"); scribd.type = "text/javascript"; scribd.async = true; scribd.src = "http://www.scribd.com/javascripts/embed_code/inject.js"; var s = document.getElementsByTagName("script")[0]; s.parentNode.insertBefore(scribd, s); })(); // ]]&gt;