LEAD: Exit polls show Gingrich leads South Carolina vote

Jan 22, 2012, 0:56 GMT

Washington - Newt Gingrich led the exit polls Saturday in the South Carolina primary vote, hinting at an upset in the Republican race for the US presidential nomination.

Four US broadcasters declared Gingrich the winner over his arch-rival Mitt Romney. CNN reported Gingrich had 38 per cent support in exit polls, followed by Mitt Romney with 29 per cent, Rick Santorum with 17 per cent and Ron Paul with 15 per cent.

Three others - MSNBC, Fox and ABC News - also declared a victory for Gingrich, with Romney, the former Massachusetts governor, coming in second. Former US Senator Rick Santorum and Texas Congressman Ron Paul were battling for third place.

'Thank you South Carolina. Help me deliver the knockout punch in Florida,' wrote Gingrich, the former Speaker of the House of Representatives, in a Tweet.

Polls closed at 0000 GMT, and official results were just trickling in.

If the official results confirm the exit polls, it would mean Gingrich surged 20 percentage points in recent days, jumping from 10 percentage points behind in the polls earlier this week.

It would also throw the Republican race wide open after Romney had seemed a shoe-in from his strong New Hampshire victory earlier this month. Santorum won the Iowa caucus, according to a final calibration of the Iowa vote released this week that took away what was thought to have been a Romney victory.

The next primary is January 31 in Florida.