CHARLESTON, S.C. — Texas Gov. Rick Perry will abandon his presidential bid and endorse Newt Gingrich, two Republican officials said Thursday, a move coming just two days before the pivotal South Carolina primary as Republican front-runner Mitt Romney struggles to fend off a challenge from the former House speaker.

Perry scheduled a news conference Thursday morning at a hotel in North Charleston to announce his decision.

The officials spoke on the condition of anonymity to avoid pre-empting the announcement.

Adding to the intrigue in the last hours of the South Carolina campaign, a bus emblazoned with Herman Cain’s name sat in the hotel parking lot where Perry was to speak. Cain, a tea party favorite, dropped out of the race late last year.

Perry has faced calls in recent days to drop out of the race in hopes of compelling conservative voters, whose support has been divided among several like-minded candidates, to rally behind Gingrich in hopes of stopping Romney.