Ted Cruz denied having anything to do with the image, which was part of an attack by an anti-Trump super PAC, Make America Awesome. (Reuters Photo)
The feud between Republican presidential contenders Donald Trump and Ted Cruz intensified on Thursday, with Cruz sharpening his attacks on Trump's conservative credentials hours after the pair exchanged comments on Twitter about each other's wives.
Cruz, the US Senator from Texas who has emerged as Trump's biggest rival for the Republican presidential nomination, opened a new front in his escalating war with the brash billionaire by linking him to disgraced New York Democratic politicians Eliot Spitzer and Anthony Weiner.
New York state holds its Republican primary April 19, with 95 delegates at stake. And while Manhattan is home to Trump's business empire, Cruz spent time there this week campaigning.
In press releases and social-media postings, Cruz highlighted Trump's history of donating not only to Spitzer, New York's former governor who resigned amid a prostitution scandal, and Weiner, the ex-US congressman who quit after tweeting lewd images of himself, but also to other New York liberals such as US Representative Charlie Rangel, Senator Charles Schumer, and New York's current governor, Andrew Cuomo.
"The real Donald Trump is a Democrat and should not be our party's nominee," Cruz said in a statement.
The Trump campaign did not respond to a request for comment, but Trump posted an Instagram video that showed former Republican presidential candidates Carly Fiorina and Lindsey Graham expressing doubts about Cruz earlier in the campaign. Both have since endorsed Cruz, saying he is in the best position to halt Trump's march toward the nomination.
The exchange deepened the hostility further between the two camps, which earlier this week erupted into full view when Trump accused Cruz of posting a nude photo of Melania Trump on Twitter.
Trump responded by threatening to "spill the beans" on Cruz's wife, Heidi.
Cruz denied having anything to do with the image, which was part of an attack by an anti-Trump super PAC, Make America Awesome.
"Donald, real men don't attack women. Your wife is lovely, and Heidi is the love of my life," Cruz said in a post on Twitter early on Thursday.
Cruz's tweet followed one moments earlier by Trump, the Republican front-runner in the race, in which he retweeted an image featuring a less-than-flattering picture of Heidi Cruz juxtaposed with a glamorous photo of Melania.
The back-and-forth was too much for Graham, who blasted both candidates in an interview on NBC's "Today" show on Thursday.
"Talk about things that people really care about, and knock this crap off because these are serious times, and you're not behaving like you want to be president of the United States," he said.
For Trump, attacking another candidate's wife may carry some political risk.
Half of US women say they have a "very unfavourable" view of the billionaire businessman, according to Reuters/Ipsos polling in March.
Cruz fared better, with 24 per cent of the 5,000 women surveyed saying they had a "very unfavourable" view of him.
The Democratic front-runner, Hillary Clinton, did worse than Cruz but better than Trump, with 36 per cent of women polled saying they had a "very unfavourable" view of her. The poll had a credibility interval of 2 percentage points.
Both Trump and Cruz are trying to garner enough delegates to win the Republican nomination ahead of the party's convention this summer. After Tuesday's contests in Arizona and Utah, Trump had 739 of the 1,237 delegates needed to win the nomination, according to The Associated Press. Cruz had 465.
Polls show Trump leading in New York ahead of its primary. And there were also indications Thursday of Trump's strength in California, where many observers believe he could clinch the nomination by winning its primary on June 7.
A new survey by the Public Policy Institute of California found that among likely Republican primary voters, Trump led with 38 per cent to 27 per cent for Cruz and 14 per cent for Ohio Governor John Kasich.
The most immediate Republican contests will be on April 5 in Wisconsin and on April 9 in Wyoming.
© Thomson Reuters 2016