Republican debate Rubio and Christie clash on track records,
Seven Republicans seeking the party's nomination to run for the White House have returned to the stage in the latest TV debate.
New Jersey Governor Chris Christie began by tearing into Senator Marco Rubio for his lack of experience.
"You have not been involved in a consequential decision, where you had to be held accountable, you just simply haven't," said Mr Christie.
Mr Rubio came third in Iowa and is seen as a rising force.
Ted Cruz is looking to build on his victory in the Iowa caucuses ahead of the New Hampshire primary election.
Debate highlights so far:
The results of Tuesday's New Hampshire primary are expected to determine whether or not some of the Republican candidates drop out.
Analysis - Anthony Zurcher, BBC News, New Hampshire
Donald Trump is back on the debate stage. Ted Cruz is coming off victory in the Iowa caucuses. But the man who may have the biggest target on his back tonight is Marco Rubio.
Thanks to his surprisingly strong, third-place finish in Iowa on Monday, the Florida senator is climbing in the polls and drawing sizeable crowds at his numerous campaign stops in New Hampshire. He's vying for mainstream establishment Republican support here - and if he's successful, it will come at the expense of fellow candidates Jeb Bush, Chris Christie and John Kasich.
If those three finish behind Mr Rubio on Tuesday, it will grievously wound their candidacies. The campaign donations likely will dry up, and the trickle of big-name endorsements coming in for Mr Rubio will become a flood.
So expect the attacks directed Mr Rubio to come thick and fast. As Mr Christie said on Friday, the goal is to knock the "boy in the bubble" off his perch.
The Iowa caucuses narrowed the field, with Kentucky Senator Rand Paul and former Pennsylvania Senator Rick Santorum withdrawing from the race after the results were announced.
ABC News, which is hosting the debate in Manchester, New Hampshire, has dropped an undercard event for low-polling candidates, leaving former Hewlett-Packard CEO Carly Fiorina as the only remaining candidate without a spot on stage.
The only woman candidate in the Republican field released an open letter describing the debate process as "broken."
Mr Trump boycotted the final TV debate before the Iowa caucuses, and later demanded a re-run of the state vote after reports that supporters of Mr Cruz, a Texas senator, had told caucus-goers that Mr Carson was dropping out of the race.
The Cruz campaign later apologised to Mr Carson, saying it was a misunderstanding.
Voters will make their choice in both the Republican and Democratic races in New Hampshire on Tuesday.
Republican debate Rubio and Christie clash on track records,
Reviewed by mohsin
on
19:59
Rating:
Reviewed by mohsin
on
19:59
Rating: