Sen. Ted Cruz (R-Tex.) continued his rhetorical onslaught against Donald Trump on Saturday, casting him as a false conservative and questioning the real estate mogul’s temperament and judgment.

“Donald’s record does not match what he says as a candidate,” Cruz told reporters after a forum in Fort Mill, S.C. “It seems Donald has a lot of nervous energy. For whatever reason, Donald doesn’t react well when he’s going down in the polls.”

The remarks are part of an aggressive escalation in a relationship that had been strategically chummy. For months, Cruz had effusively praised Trump, stating there was a benefit to having the New Yorker in the race and chiding the media for “the little game” of pitting Republicans against one another.

Thursday’s Republican debate marked the end of that. Cruz, with unconcealed delight, chided Trump for raising questions about whether he met the Constitution’s “natural born” standard for president; with less success, he started raising questions about whether a Manhattan mogul could be trusted by conservatives.

This is what Republican presidential candidate Ted Cruz means when he criticizes Donald Trump's "New York values." (Thomas Johnson/The Washington Post)

Trump escalated his attacks Saturday morning, saying in a tweet that additional lawsuits will be filed questioning Cruz’s eligibility to be president. At a rally in Portsmouth, N.H., he knocked Cruz for not reporting loans from Goldman Sachs and Citibank that he used to fund his 2012 Senate campaign.

“How do you control . . . these big powerful banks, you’re a senator and yet you owe them money with a personal guarantee?” Trump said to a crowd of about 500.

Trump said Goldman “owns” Cruz and he will “Do anything they demand.” Cruz’s wife is on leave from her job as a managing director at Goldman.

In another tweet, Trump called Cruz the “ultimate hypocrite,” linking to a story about how Cruz attended an event at the New York home of two wealthy gay businessmen.

Cruz pointed to the Wall Street Journal/NBC News poll that shows him beating Trump in a two-man race — although Trump leads the entire field.

“I imagine it pulled him out of bed this morning and sent him tweeting and tweeting and tweeting. I think in terms of a commander in chief, we ought to have someone who isn’t springing out of bed to tweet in a frantic response to the latest polls,” Cruz said. “I think the American people are looking for a commander in chief who is stable and steady and a calm hand to keep this country safe.”

At Fox Business Network’s debate in North Charleston, S.C., candidates vied for momentum ahead of the Iowa Caucus. Washington Post reporter Robert Costa names the winners and losers from that night. (Dalton Bennett/The Washington Post)

Cruz’s campaign also went on the offensive, tweeting and emailing a video of Trump on “Meet the Press” from 1999, in which Trump called himself “very pro-choice” and admitted that he viewed gay rights differently from a voter in the heartland.

“I lived in New York City and Manhattan my whole life, so my views are a little bit different than if I lived in Iowa,” Trump said.

Trump’s campaign manager declined to discuss the candidate’s latest attacks on Cruz.

Cruz said last week that Trump represents “New York values,” stating during the debate that they are “socially liberal or pro-abortion or pro-gay-marriage, focus around money and the media.”

Trump offered an emotional defense of the city during the debate, speaking movingly of the 9/11 attacks. Cruz seemed lost, applauding along with the audience. It took him most of a day to formulate a comeback, delivering an “apology” to New Yorkers for the liberal elected officials who were depriving them of safety and freedom, then calling Yahoo News to ask readers to watch the 1999 ­interview.

Cruz continued on Saturday, saying that the “New York values” phrase came from Trump himself.

“Being very, very, very pro-choice, supporting partial birth abortion and being open to gay marriage,” said Cruz. “That’s what Donald Trump described as New York values.”

He also stated that Trump gave money to Democratic presidential contender Hillary Clinton, New York Gov. Andrew M. Cuomo (D) and other Democrats.

“It’s a fair inference that he supports their policies. So I understand that he is feeling defensive about my observation,” Cruz said.

Cruz spokesman Rick Tyler said that the campaign will highlight contrasts between Cruz and Trump to illustrate that voters can be confident that Cruz has “guiding principles to make critical decisions as president and commander in chief,” he said.

Trump “has policy proposals that just don’t seem serious,” Tyler said.

Chad Sweet, the Cruz campaign’s chairman, said Cruz’s comments are direct responses to attacks that Trump lodged against Cruz about his birthplace and religion — attacks that, Sweet noted, Trump said during the debate were sparked by Cruz’s rising poll numbers.

“When we’ve responded we’ve attempted to stay in the counterpunch mode, hitting back on specifics about what he has been attacking us on,” Sweet said.

When asked why Cruz decided to go after Trump this past week, Tyler said, “We have three weeks to go” until the Iowa caucuses.

“Donald Trump started the fight with us; we’re glad to finish it,” Tyler said.

The two had played nice earlier in the campaign, with Cruz repeatedly calling Trump his friend, meeting with him in July at Trump Tower and inviting him on a trip to the U.S.-Mexico border that Cruz couldn’t make because the Senate had votes scheduled. Cruz invited Trump to a Capitol Hill rally against the Iranian nuclear deal in September.

At the time, Cruz told NBC News that Trump’s success had been “immensely beneficial for our campaign.” His assumption, confidently stated on live TV, was that “as voters get more educated,” they would graduate from Trump’s campaign to his.

But that hasn’t happened, and Cruz is now on the offensive, trying to cast himself as a candidate with superior judgment and values.

The feud may have its greatest impact in Iowa, where the two candidates are in a tight race with widely overlapping constituencies. Cruz’s criticisms of New York values threatens to undermine Trump’s support among the state’s evangelical Christians, who have made up a majority of Iowa’s caucus-goers and have fueled victories for Rick Santorum and Mike Huckabee in the past two election cycles.

Cruz’s support is concentrated among white, born-again Christians, but he leads Trump by a modest 33 to 19 percent among this group in a Fox News poll this month, despite winning several key endorsements from evangelical leaders. The two candidates are also battling to appeal to voters’ frustrations with Washington and the national Republican Party. A Des Moines Register-Bloomberg News poll, which found Cruz at 25 percent and Trump at 22 percent, showed indicated two-thirds of each candidate’s supporters say they are backing anti-establishment Republicans, compared with just over half of all likely caucus-goers.

Cruz’s success at locking up evangelical and tea-party support has left him with few defenders. Huckabee, the former Arkansas governor, arrived at the South Carolina Tea Party Convention here several hours before Cruz was set to speak, and in a short news conference, he passed up two chances to criticize Trump. If the mogul had evolved on social issues, Huckabee said, it had happened over “15 years, not 15 minutes,” a fine contrast with the other Republican candidates.

“I think Donald Trump did a great job the other night of talking about the kind of values that we saw and the sacrifice of New Yorkers after 9/11,” said Huckabee, recalling his own visit to the “smoldering” World Trade Center. “I think everybody in the world was just absolutely amazed at how the people of that city pulled together and rebuilt.”

But when Huckabee took the stage, he saw hundreds of supporters of Trump or Cruz. At least a hundred of the roughly 600 tea party activists who made it to Myrtle Beach wore T-shirts printed with one of the candidates’ names. Few were interested in the fight raging across the media.

“He wasn’t beating up Trump when he said that about New York, and Trump had a really good comeback in the debate,” said Charlie Fowler, a Charleston conservative activist wearing a shirt from one of the first tea-party gatherings in 2009. “But the values issue is real. All you really have to do is look at a map — blue on the coasts, red in the middle.”

Sandra Inman, a Cruz supporter from Jackson, Miss., attending the South Carolina Tea Party Coalition Convention, said she could not support Trump but understood why people did.

“He changed the conversation for the first time in my lifetime,” Inman said. “The tea party people I know who support him know that he’s changed. They are lots of people who had Democratic leanings and came around.”

Speaking in contested territory at the convention, the two candidates dialed down the rhetoric. Cruz never mentioned Trump by name. Instead, he suggested that no one who had shared the debate stage had fought with his vigor against legalizing gay marriage, the Affordable Care Act or Planned Parenthood. “No one in history ever grew a backbone after they got to 1600 Pennsylvania Avenue,” he said. In interviews after the speech, Trump’s fans in the crowd did not interpret that as a criticism.

Trump, who spoke for more than 45 minutes, did not mention Cruz until a reference to the Goldman loan. “He didn’t report the loans,” he said as some wearing Cruz shirts booed. But he spent more time mocking a familiar target: Jeb Bush. Trump’s biggest applause came when he said “zero” voters would follow Sen. Lindsey O. Graham (R-S.C.) and endorse Bush.

“Why’s he attacking me?” Trump said. “He’s got to knock out seven or eight guys before he gets to me.”

Zezima reported from Washington. Patrick Svitek in Fort Mill, Jose A. DelReal in Portsmouth, and Jenna Johnson and Scott Clement in Washington contributed to this report.