Voting got underway on Tuesday in America’s so-called ‘Super Tuesday’ race to win the Republican nomination for the White House.
First up was Ohio, a swing state and said to be the largest battleground, with voters in nine other states due to take part in separate contest later.
The vote was likely to help pick the candidate who will go forward to face Barack Obama in the presidential elections in November.
Going into Super Tuesday, analysts said Mitt Romney and Rick Santorum were neck and neck after Romney won the last five contests.
At stake are 419 of the 1,144 delegates needed to win the party’s nomination.
Former House of Representatives Speaker Newt Gingrich and Texas Congressman Ron Paul are also in the race but seen as outsiders.