With 99 per cent of the votes counted in Alabama, Santorum had 35 per cent over Newt Gingrich and Mitt Romney with 29 per cent each, television networks reported.
The race was closer in Mississippi, where Santorum held 33 per cent over Gingrich's 31 per cent and Romney's 30 per cent, with 99 per cent of the votes counted.
Romney won Hawaii with 45 per cent against 25 per cent for Santorum with 99 per cent of the votes counted. The former Massachusetts governor also won American Samoa, CNN reported.
The results signalled that the three-way scramble for the Republican nomination will drag on longer than pundits had expected. It also dealt another blow to the Republican Party establishment, which had expected Romney, 65, the former governor of Massachusetts, to easily sew up victory early in the race.//DPA