Rick Santorum revels in Alabama and Mississippi double
US Republican presidential candidate Rick Santorum has won the Mississippi and Alabama primaries, upsetting front-runner Mitt Romney once again.
The social conservative ridiculed his rival's third-place finish in both contests, despite having far outspent his competitors.
Mr Santorum's double also dashed the comeback hopes of Newt Gingrich, who came second in each vote.
Wins in the Hawaii and American Samoa caucuses were Mr Romney's consolation.
With nearly all the votes counted, Mr Santorum won 33% in Mississippi to 31% for Mr Gingrich and 30% for Mr Romney.
In Alabama, Mr Santorum had 35% and Mr Gingrich and Mr Romney each had 29%, although Mr Gingrich was slightly ahead of Mr Romney.
The former Massachusetts governor still has a commanding lead in the hunt for delegates who will anoint the Republican nominee at the party convention in August.
The partial allocation of delegates from Tuesday's voting states left Mr Romney with 494 out of the 1,144 needed to win the race, according to an Associated Press tally. Mr Santorum had 251, Mr Gingrich 131 and Ron Paul 48.
However, Santorum campaign spokesman John Brabender told CNN that unbound delegates could still switch their votes to his candidate.
On Wednesday, former Pennsylvania Senator Santorum campaigned in the US island territory of Puerto Rico, which holds its primary on Sunday.
The next crucial contest for Mr Romney is the Midwestern state of Illinois, which votes next Tuesday.
The former governor's campaign has already spent $1m (£636,700) on television adverts in the state.
Another $2.4m of spending is planned by a pro-Romney group.
Despite his campaign's deep pockets, Mr Romney yet again struggled to win over conservatives on Tuesday amid misgivings over his record as governor of the liberal state of Massachusetts.
His Mormon faith may also have hurt him in both states, where exit polls indicated more than seven out of every 10 voters were white evangelical Christians.
Mr Santorum, a devout Catholic and opponent of abortion and gay marriage, told Fox News that voters "want a conservative nominee".
"I think that's what it is coming down to," he said. "The best way to get that is for us to have a one-on-one opportunity with Governor Romney."
Pressure is now expected to mount on Mr Gingrich, a former House of Representatives Speaker, to drop out so conservatives can rally behind Mr Santorum in challenging Mr Romney.
In his concession speech, Mr Gingrich also could not resist pouring scorn on Mr Romney, saying: "If you're a front-runner and you keep coming in third, you're not much of a front-runner."
His failure to win on Tuesday was a serious blow to Mr Gingrich, who has only won two contests, one of which was his home state.
The Romney campaign had been hoping for at least one Deep South victory on Tuesday to argue that it was now time for the party to unite behind him and focus on November's general election against President Barack Obama.
Before Tuesday's results were in, Mr Romney told CNN that Mr Santorum was reaching the "desperate end of his campaign".
The former Massachusetts governor did not speak on Tuesday night as he travelled to New York for fundraising events.
But he said in a statement: "With the delegates won tonight, we are even closer to the nomination."