Members of the media view the Republican presidential primary debate hosted by ABC News at the St. Anselm College in Manchester, N.H., Feb. 6, 2016.
Members of the media view the Republican presidential primary debate hosted by ABC News at the St. Anselm College in Manchester, N.H., Feb. 6, 2016.

MANCHESTER N.H. - U.S. Republican presidential candidates talked tough on foreign policy and launched fierce attacks on their rivals as they faced off at a debate in New Hampshire Saturday.

The debate took place just three days before New Hampshire’s presidential primary – a crucial election that could make or break several of the candidates’ presidential bids.

Apparently sensing that pressure, several of the lesser-polling candidates came out swinging at their opponents as soon as the debate began.

None was more aggressive than New Jersey Governor Chris Christie, who took aim at Florida Senator Marco Rubio early in the debate. “He simply does not have the experience to be president of the United States and make these decisions,” said Christie of Rubio, a first-term senator.

New Jersey Gov. Chris Christie points toward Repu
New Jersey Gov. Chris Christie points toward Republican presidential candidate, Sen. Marco Rubio at the other end of the stage as retired neurosurgeon Ben Carson looks on

Christie accused Rubio of repeating a “memorized 25-second speech” he uses at campaign events, and said the senator has accomplished little during his time in Congress.

Rubio appeared rattled by the attack, but he instead focused on criticizing President Barack Obama, who he said was embarking on a “systematic effort to change America.”

Rubio is seen as a favorite of the establishment Republican wing, especially after he secured a better-than-expected third-place finish in Iowa last week, the nation’s first nominating contest.

Candidates Jeb Bush, left, and Donald Trump, right
Candidates Jeb Bush, left, and Donald Trump, right, spar as Sen. Marco Rubio listens in the middle during a Republican presidential debate at St. Anselm College, Feb. 6, 2016, in Manchester, N.H.

Trump focuses on issues

Donald Trump was center stage at the debate.

The real estate mogul leads polls in New Hampshire and needs a good result there after his disappointing second-place finish in Iowa.

Apparently wanting to protect his New Hampshire lead, Trump was less combative than usual, focusing more on policy than on the signature personal insults he has relied on in the past.

Trump defended his tough proposals on immigration, including building a wall along the U.S. border with Mexico. He also said he would ramp up the fight against Islamic State. “You’ve got to knock the hell out of their oil,” said Trump. He also vowed to bring back the use waterboarding while interrogating terror suspects. “And I’d bring back a hell of a lot worse than waterboarding,” Trump added.

Republican presidential candidate Sen. Ted Cruz ge
Republican presidential candidate Sen. Ted Cruz gestures while talking

Cruz defends ‘carpet bombing’ plan

Texas Senator Ted Cruz also vowed to bring back “whatever enhanced interrogation methods” are necessary to keep the country safe, but not “in any sort of widespread use.”

Cruz stood by his recent calls to “carpet bomb” Islamic State targets in Syria and Iraq. He said the airstrikes would not be indiscriminate, but would instead target specific, strategic sites.

The Texas senator’s campaign has been on the upswing since his surprise win in Iowa. But the evangelical Christian, who calls for a radically smaller federal government, faces a tough challenge in New Hampshire, where voters traditionally prefer more moderate candidates.

Given those voter preferences, several more centrist and low-polling Republican candidates have staked their entire campaigns on doing well in the so-called Granite State. That group includes Christie, ex-Florida governor Jeb Bush and Ohio Governor John Kasich.

Bartenders work at McGarveys Bar in Manchester, N.
Bartenders work at McGarveys Bar in Manchester, N.H., as the Republican presidential debate is shown on televisions

Carson attacks Cruz

Also struggling to keep his presidential bid alive is retired neurosurgeon Ben Carson. Once a  favorite of many evangelicals, Carson has seen his standing in the polls consistently deteriorate in recent weeks.

Carson used the debate stage to attack Cruz, whose staffers incorrectly spread reports last week that Carson was dropping out of the race.  The move is an example of “Washington ethics,” Carson said. “That’s not my ethics. My ethics say, ‘Do what’s right.’”

In response, Cruz portrayed the incident as a misunderstanding, saying his staff had seen a media report implying that Carson had dropped out.

In reality, Carson had temporarily stepped away from the campaign, purportedly so the candidate could return home and get a fresh set of clothing.

Trump has also repeatedly criticized the Cruz campaign over the matter, even arguing that the Texas senator “stole” the Iowa vote, and Trump is threatening to legally challenge the result.

During his closing statement, Trump again brought up the issue, saying that Cruz only won Iowa “because he got Ben Carson’s votes.”

Republican presidential candidate Sen. Marco Rubio
Republican presidential candidate Sen. Marco Rubio answers a question

North Korea

The seven presidential hopefuls also addressed the threat of North Korea, which minutes earlier reportedly carried out a ballistic missile test in violation of U.N. sanctions.

Jeb Bush took the firmest stance against Pyongyang, saying “if a preemptive strike (against the North) is necessary to keep us safe, then we should it.”

Cruz refused to make such a promise, instead saying he would first need to see intelligence briefings.

Trump said his Pyongyang strategy would start with China, North Korea’s closest international ally: “Let China solve that problem. They can do it quickly and surgically,” he said.

“They do not understand anything but toughness and strength,” said Christie of North Korea’s government. “We need a strong commander in chief who will look these folks in the eye and say, ‘We will not put up with this.’”

WATCH: Young Voters at Debate Party Enthusiastic About Election

Shrinking field

The debate, held at Saint Anselm College in Manchester and televised nationally on ABC, was the eighth time Republican candidates have faced off at such a forum. This is the smallest group of candidates of any of the debates, thanks to a shrinking field of candidates.

Kentucky Senator Rand Paul, former Arkansas governor Mike Huckabee, and former Pennsylvania senator Rick Santorum all dropped out of the race following disappointing results in Iowa.

Democratic presidential candidate Sen. Bernie Sand
Democratic presidential candidate Sen. Bernie Sanders speaks during a campaign stop at the Franklin Pierce University Fieldhouse, Feb. 6, 2016, in Rindge, N.H.

Democratic race

The remaining candidates are competing to become the Republican Party’s nominee and face off in November’s general election against either former secretary of state Hillary Clinton or Vermont Senator Bernie Sanders.

Polls show the self-described democratic socialist Sanders with a big lead over Clinton in New Hampshire, which neighbors his home state. The senator is also closing in on Clinton in several recent national polls.

Both Democratic candidates held rallies across New Hampshire Saturday, making their final arguments to undecided voters.

A confident-looking Sanders made an appearance at Franklin Pierce University in Rindge, New Hampshire, where he repeated his call for a “political revolution.”

“If we can bring out a decent vote on Tuesday I'm confident we're going to win," Sanders told the group of several hundred mostly young people.

Democratic presidential candidate Hillary Clinton
Democratic presidential candidate Hillary Clinton reacts as former Secretary of State Madeleine Albright introduces Clinton at a campaign event at Rundlett Middle School, in Concord, N.H., Saturday Feb. 6, 2016.

Clinton toured the state’s southern region. At a rally in Concord, she fended off a voter question over her trustworthiness. “You vet us. You take second, third and fourth looks,'' Clinton told supporters during a rally in Concord. "And I hope you will look hard at this.''

Clinton, whose victory in the Democratic race once seemed certain, has been dogged by a controversy over her use of a personal and unprotected email server during her time as the top U.S. diplomat.