Voting is underway in the US state of New Hampshire in the two-person race for the Republican presidential nomination. Donald Trump faces Nikki Haley, who he appointed to the post of US ambassador to the United Nations when he was president.

The polls are open to members of the Republican Party as well as undeclared voters.

The political analysis website RealClearPolitics shows as of Monday, Trump's average approval rating in New Hampshire opinion polls stood at 54.9 percent. Haley's was at 36.7 percent.

After Trump's outright victory in the Iowa caucuses last week, Haley needs to win the New Hampshire primary or at least finish in a very close second place.
Some observers say if Haley fails to do either, it would likely result in Trump securing the Republican Party nomination.