Rick Santorum has cruised to victory in the Louisiana Republican presidential primary but still trails Mitt Romney by a wide margin in the national delegate count for the party nomination.
Mr Romney, a former Massachusetts governor, was projected to finish second. Former House of Representatives Speaker Newt Gingrich was third, but immediately rejected suggestions he should drop out.
Texas congressman Ron Paul came in fourth. Mr Santorum had strong support in all income groups except for the very wealthy, and solid backing from conservative and religious voters in the Deep South state.
"The people of Louisiana sent a loud and clear message - this race is far from over," Mr Santorum said in Green Bay, Wisconsin, where he watched the election results after making a series of campaign stops.
Mr Santorum, a socially conservative former US senator from Pennsylvania, has done well in the Deep South, winning Mississippi and Alabama earlier this month.
In all, Mr Santorum has won seven state contests in March. Yesterday's primary allocated only 20 of Louisiana's 46 total Republican delegates as candidates spar for the right to take on Democratic president Barack Obama in the November general election.
The rest of the delegates will be allocated at the state party convention in June.
With 91 per cent of the precincts reporting, Mr Santorum had 49 per cent of the vote, Mr Romney 26 per cent and Mr Gingrich 16 per cent. If those totals hold, Mr Santorum and Mr Romney would both gain delegates from Louisiana, with Mr Gingrich shut out.
Exit polls showed that 47 per cent of Republican primary voters identified themselves as "very conservative," and of those Mr Santorum beat Mr Romney by 52 per cent to 24 per cent.
Mr Santorum also won majorities among voters calling themselves "somewhat conservative" or "moderate," and those who said that religion matters a lot in public life.A Republican candidate needs 1,144 delegates to secure the party's nomination.
CNN's current delegate count puts Mr Romney well ahead, with 563 delegates to Mr Santorum's 259.
Reuters