Mitt Romney, front-runner for the Republican Party nomination, speaks to supporters in Boston, Massachusetts.

The state where he used to serve as governor was one of six that he won on a pivotal day in the nomination race, dubbed 'Super Tuesday'.

(SOUNDBITE) (English) REPUBLICAN PRESIDENTIAL CANDIDATE MITT ROMNEY:

"We're going to take your vote, a huge vote tonight in Massachusetts, and take that victory all the way to Whitehouse"

Romney also secured victories in Idaho, Vermont, Virginia, Alaska and Ohio - the night's biggest prize.

But despite this he was still unable to deliver the knock out blow to his rivals that his supporters had been hoping for.

Rick Santorum, who pushed Romney all the way in Ohio, secured victory in three states and insisted he was in the race until the end.

(SOUNDBITE) (English) REPUBLICAN PRESIDENTIAL CANDIDATE RICK SANTORUM:

"Tonight, it's clear. It's clear. We have won races all over this country, against the odds. Whey they thought 'oh okay he is finally finished', we keep coming back.

Newt Gingrich meanwhile celebrated winning his home state of Georgia, while Ron Paul has yet to score any state victories in the primaries.

Romney is still the favourite to challenge Democratic President Barack Obama in November.

This is despite his inability to win over large swathes of the Republican base, who view his past as a moderate Massachusetts governor with suspicion.

Simon Hanna, Reuters.