Republican debate: Mitt Romney under fire
US Republican front-runner Mitt Romney has come under fire from fellow contenders ahead of Tuesday's primary vote in the state of New Hampshire.
At a nationally televised debate on Sunday, the former Massachusetts governor's economic programme was called "timid" and his conservative credentials were also questioned.
Mr Romney has a lead over his rivals since his narrow win in Iowa last week.
The winner will challenge President Barack Obama in November's election.
Six candidates remain in the race for the Republican nomination.
Primaries and caucuses will take place in every US state over the next few months before the eventual Republican candidate is crowned at the party convention in August.
But votes in New Hampshire, South Carolina and Florida this month could well shape the race for the nomination.
Sunday's debate was the second in less than 24 hours. It was co-hosted by NBC's Meet the Press, the New Hampshire Union Leader and Facebook - with questions being sent over the social networking site.
Former House of Representatives speaker Newt Gingrich accused Mr Romney of "pious baloney" for saying he was not a career politician.
"Just level with the American people," Mr Gingrich urged him.
To which Mr Romney quipped: "Politics is not my career. My life's passion has been my family, my faith, my country."
Mr Gingrich described Mr Romney as a "relatively timid Massachusetts moderate" - adding, "I think he'll have a very hard time getting elected."
But Mr Romney replied: "I'm very proud of my record and I think the one thing you can't fool the people of New Hampshire about is the record of a governor next door."
Rick Santorum, the former Pennsylvania senator who lost the Iowa caucus by just eight votes, questioned why Mr Romney had not sought a second term as Massachusetts governor.
"Why did you bail out? And the bottom line is, I go fight the fight," Mr Santorum said.
Mr Romney adopted the same tactic as during Saturday's debate, largely refraining from making digs at his opponents - though he pointed to Jon Huntsman's period as ambassador to China under Mr Obama.
Mr Huntsman replied on Sunday: "I was criticised last night by Governor Romney for putting my country first. He criticised me while he was out raising money. I want to be very clear. I will always put my country first."
Mr Romney's three main rivals - Mr Santorum, Mr Gingrich and Texas congressman Ron Paul - attacked each other again.
Mr Santorum said Mr Paul had "never really passed anything of any importance".
"One of the reasons people like Congressman Paul is his economic plan. He's never been able to accomplish any of that, has no track record of being able to work together. He's been out there on the margins and has really been unsuccessful in working together with anybody to do anything."
And when asked about President Obama's patriotic credentials, Rick Perry said: "We have a president that's a socialist. I don't think our founding fathers wanted to make our country as socialist country."