New Orleans:
Republican presidential candidate Rick Santorum won the Louisiana primary on Saturday, US media projections said, giving his flagging White House campaign a much needed boost.
CNN, Fox News and MSNBC called the southern state in Mr Santorum's favour shortly after polls closed, with partial results showing him 39 per cent of the vote, well ahead of Republican frontrunner Mitt Romney, at 30 per cent.
The forecasts were based on very early returns from the ballot, which put veteran politician Newt Gingrich on 22 per cent and fourth-placed Libertarian candidate and Texas congressman Ron Paul a long way back on five per cent.
"In spite of Romney heavily spending and campaigning there, the people of Louisiana saw through the lies and negative campaigning to vote for the authentic conservative," said Mr Santorum in a victory statement.
"Our campaign has now won 11 states... proving we can win in the West, South and Midwest.
"People want an authentic, strong conservative leader to take on (President) Barack Obama and not someone who just talks a good conservative game," Mr Santorum added, in a jibe likely aimed at Romney.