Kathleen Hennessey and Scott Bauer

RINGSTED, Iowa: Lagging Republicans jostled for second place in their crowded field, while Hillary Clinton faced more email troubles Friday as the presidential contenders barreled toward a final weekend of campaigning before Iowa’s crucial caucuses.

Most of the candidates were scattered across Iowa in a last-chance try to gin up enthusiasm, sharpen attacks and set expectations — all part of efforts to emerge from Monday’s voting with momentum and a slice of the spotlight.

Some were also burdened with playing defense.

Clinton’s campaign deflected fresh suggestions that the former secretary of state’s use of a private email server for government business may have posed a security risk. The news heightened some Democrats’ fears that the email controversy could dog their front-runner well into this year’s campaign.

Speaking to NBC News before the news broke, Clinton dismissed the potential impact of the simmering issue.

“There was never any information sent or received that was marked classified to me,” she said. “I just don’t see it as anything that will in any way cause any voter — a voter with an open mind — to have any concerns.”

On the Republican side, Ted Cruz tried to kick back against the rival closest on his heels, unleashing tough new television ads labeling Florida Sen. Marco Rubio “the Republican Barack Obama.” Rubio said the ad blitz was a sign Cruz, after months of cruising to the top of the heap, was starting to sweat.

The back-and-forth was a reminder that toughest battle in the GOP race was at the top. With Donald Trump’s lead holding steady, the rest of the field is left in a dogfight for second or third — or even just “better than expected.”

In that battle, the knives were out Friday for Cruz, who has campaigned as the one true conservative in the race.

New Jersey Gov. Chris Christie tried to poke holes in that claim, telling Cruz to just “tell the truth” on flip-flopping on immigration. Rubio, meanwhile, said Cruz “has a lot to answer for” on the issue.

Not to be left out, Trump called Cruz an “anchor baby,” a new twist on his persistent claims that Cruz, who was born in Canada to a U.S. citizen, may not be eligible to hold the presidency.

“Ted Cruz is an anchor baby in Canada, but ­Canada doesn’t accept anchor babies. ... I think that’s one of the reasons he’s a nervous wreck, too,” Trump said at a rally in Nashua, N.H., where the real estate magnate was already looking past Iowa.

As he closed out his Iowa bid, Cruz kept to his message and a pugnacious style that has repelled establishment Republicans. He warned Iowans not to fall for false promises. He showed no deference for other contenders or for party elder Bob Dole, who has spoken out against a possible independent run by Michael Bloomberg because he fears that could result in a win for Cruz.

As for Monday’s voting, Cruz campaign manager Jeff Rose said the organization’s figures show there are 9,131 Iowans choosing between Cruz and Trump, 2,807 choosing between Cruz and Rubio and 3,185 deciding between Cruz and retired neurosurgeon Ben Carson.