Super Tuesday: Romney fails to deliver knockout

UPDATED 9PM Mitt Romney gained a narrow win over Rick Santorum in Ohio and added Alaska as well to extend his lead as the main contender for the Republican presidential nomination.

But Mr Santorum's strong showing in Ohio, where he started as the close favourite, indicates he will stay in the contest after his social conservative view swept up three of the 10 states during Super Tuesday.

The other two contenders, Newt Gingrich and Ron Paul, are nowhere in the running, although Mr Gingrich had a home state win in Georgia to add to his campaign first in South Carolina.

The next round of primares is in a set of southern states -- Mississippi and Alabama (Mar 13) and Louisiana (Mar 24) -- where Mr Romney's economic focus may be less favoured than than the issues favoured by Messrs Santorum and Gingrich.

UPDATED 7PM Mitt Romney adds Idaho to his wins and is still locked in a tight contest with Rick Santorum to carry Ohio.

With 99% of the Ohio vote counted, Mr Romney had 37.9% of the vote to Mr Santorum's 37% - a margin that is likely to give Mr Santorum heart to stay in the race. 

MORE - RealClearPolitics.com: live Super Tuesday results

UPDATED 5PM Mitt Romney and Rick Santorum have shared three wins each in the Super Tuesday round of primaries and caucuses in 10 states.

Voters have so far failed to give Mr Romney the decisive win he needed to knock out Mr Santorum.

Mr Santorum has picked up North Dakota along with Tennessee and Oklahoma, while Mr Romney has bagged Virginia, Vermont and Massachusetts.

They are both head-to-head in Ohio, the most critical primary being decided today. The only other states yet to announce results are Alaska and Idaho.

UPDATED 4PM Rick Santorum adds Oklahoma to his win in Tennessee. Both were expected. Ohio remains critical for both Santorum and Mitt Romney.

UPDATED 3PM Rick Santorum wins Tennessee, one of two states he was favoured to win, the other being Oklahoma.

UPDATED 2.30PM Mitt Romney wins his home state of Massachusetts, adding to his other easy victories in Virginia and Vermont.

Mitt Romney looks to have taken a commanding lead in the Republican presidential race by bagging Virginia, one of the 10 states in Super Tuesday contests.

He is expected to win his home state of Massachusetts and nearby Vermont. He is also favoured in Idaho, where roughly one-in-four voters shares his Mormon faith.

Rival candidate Newt Gingrich, who is running third to Mr Romney and Rick Santorum, bagged a home-field win in Georgia.

In the undeclared states, Ohio is the most important, with Mr Santorum seen to be losing ground to Mr Romney.

Attention is also focused on Tennessee, where Mr Santorum has led public opinion polls.

Mr Gingrich was expected to win in Georgia, the state he represented in Congress for 20 years.

Mr Romney was favoured in Virginia, where Messrs Santorum and Gingrich didn't make the ballot.

The fourth candidate, Ron Paul, of Texas, is hoping for his first victories in the in Alaska and North Dakota caucuses.

Voting has just closed in Vermont. It will be followed by Ohio (1:30 pm NZ time) with Tennessee, Massachusetts and Oklahoma (2pm NZ time) after that.

Results from North Dakota, Idaho and Alaska are expected later today or early tomorrow (NZ time).