NEWBURY, N.H. — As attacks escalate in the Republican presidential campaign, Ohio Gov. John Kasich is vowing to stay positive and is calling on his opponents to take down their negative ads and to urge their super PACs to do the same.

“People ought to take down negative ads and tell the people in the last week what they’re for,” Kasich told reporters Tuesday after holding a town hall here. “I just think it will work for me by being positive, and I wish all of them would just knock it off and let’s just judge who’s got the best program and the best plan and the best message and the most town halls.”

Kasich has staked his campaign on a strong finish in New Hampshire, and the surprisingly strong performance of Sen. Marco Rubio (Fla.) in Iowa on Monday night puts a potentially significant obstacle in his path.

During his conversation with voters, Kasich outlined his economic, tax and regulatory agenda and said, “I’m ready to roll. What I worry about is people who are not ready to roll and we’re going to drift for four more years.”

Asked which of his rivals he had in mind, he said, “Nobody in particular. I just want people to be aware that experience in that town matters and they can draw their own conclusions …” Pressed as to whether Rubio was prepared to handle the presidency, he said, “I’m not getting into talking about other candidates. I’m just talking about my own candidacy.”

Kasich said he has been pummeled by negative ads from his rivals and asserted that were it not for that he might be in even better shape in the Granite State. “Our people look at that kind of thing and say how much higher would we have been if we had not been subjected to multiple millions of negative ads,” he said. “We’re hanging in there. Our voters are tough and secure and we just need to keep going.”

Kasich ran poorly in Iowa on Monday, finishing with just 2 percent of the vote, though he spent little time there.

Pointing at the weak showing by former Florida governor Jeb Bush, who got just 3 percent, Kasich said, “I think Bush spent about $30 million and we spent about $150,000, and we actually did better than I thought we’d do.”