(REUTERS) -- Former Massachusetts Governor Mitt Romney won the New Hampshire Republican U.S. presidential primary on Tuesday by a comfortable margin -- his second straight victory in the race to become his party's choice to challenge Democratic President Barack Obama on Nov. 6.

With 79 percent of the precincts reporting, Romney had captured 38 percent of the vote; Ron Paul, 23 percent; Jon Huntsman, 17 percent; Newt Gingrich, 10 percent, and Rick Santorum, 10 percent.

Based on early returns with about 10 percent of the vote counted, U.S. television networks declared Romney the victor. With about 15 percent of the vote counted, the networks said Romney had won 36 percent of the vote, with Congressman Ron Paul in second with 25 percent.

The New Hampshire primary is the second contest in the state-by-state battle for the Republican presidential nomination to face Obama. Romney narrowly won the first contest, the Iowa caucuses, on Jan. 3.

The former investment firm chief scored the clear victory despite rivals' fierce 11th-hour attacks painting him as a heartless corporate raider who enjoys cutting jobs. Romney's stint as a relatively moderate governor of neighboring Massachusetts has also sparked skepticism from conservatives.

Voters responded to Romney's claim that his private sector experience would help him galvanize the weak U.S. economy.

I was looking for someone who is smart, knows our country, knows the financial system and how to get the country moving again with jobs, said Eddie Carr, a 77-year-old school bus driver who voted for Romney. I think it was right to vote for him. I think he can get the country going.

Paul, a congressman from Texas known for his libertarian views, beat out Jon Huntsman, a moderate former U.S. ambassador to China, for second place in New Hampshire, the small New England state known for its independent streak and outsized role in presidential campaigns. Huntsman had about 17 percent of the vote.

Romney became the first Republican who is not an incumbent president to win the first two early voting states, after his slim eight-vote victory over former Pennsylvania Senator Rick Santorum a week ago in the Iowa caucuses.

But he might face a bigger challenge in the next primary in South Carolina on Jan. 21, where the economy is weaker and conservatives make up a larger slice of the electorate.

A Reuters/Ipsos poll on Tuesday showed Romney was way ahead of rival Republicans nationally, with 30 percent support. He still trailed Obama by five points in the White House race.

(Additional reporting by Ros Krasny and Steve Holland in Manchester andPatricia Zengerle and Jeff Mason in Washington.)