Santorum wins big in US Republican primaries

In the United States, former Pennsylvania Senator Rick Santorum swept primaries in Alabama and Mississippi Tuesday night, casting doubt on the ability of front-runner Mitt Romney to seal the race for the Republican presidential nomination.

Former House speaker Newt Gingrich was betting on a strong showing in the South, but only managed second in both races.

There were 107 Republican National Convention delegates at stake on Tuesday, 47 in Alabama, 37 in Mississippi, 17 in Hawaii caucuses and six more in caucuses in American Samoa.

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