Donald Trump jabs Ted Cruz over his Canada birth

Republican frontrunner Donald Trump has attacked Ted Cruz over his birth in Canada, saying it raised questions about his presidential eligibility.

In the latest Republican debate for White House hopefuls, Mr Trump told his rival: "There's a big question mark over your head."
The US constitution says the president be a "natural born citizen" of the US.
Issues of national security, the economy and foreign policy have also played heavily in the debate.
In the polls, the pair are leading the four other candidates who are also on the stage in North Charleston.
The debate comes just two weeks before the first real test of the campaign, when voters in Iowa pick their Republican and Democratic choices for president.
Highlights so far:

• Mr Cruz opened by expressing disgust over the detention of US sailors by Iran this week
• He also defended a controversy over his campaign finances in 2012, alleging bias in the media
• Mr Trump defended his call for a halt on refugees, saying they were a "Trojan Horse" bringing in people who would harm the US, pointing to the terror attack in San Bernardino as evidence
• Florida Senator Marco Rubio said Hillary Clinton's handling of the Benghazi attacks disqualifies her to be president
• Florida Governor Jeb Bush said that the investigation into Ms Clinton's private emails would mean her first 100 days in office would see her going "between the White House and the court house"

The event hosted by Fox Business Network comes after days of Mr Cruz and Mr Trump taking shots at each other, shattering a months-long period of goodwill between the two men.
The start of hostilities began a week ago when the billionaire businessman started raising questions about whether the Texas senator's birth in Canada put his eligibility in doubt.
But on the debate stage on Thursday night, Mr Cruz said there was "zero chance" of a lawsuit succeeding, because the constitution's definition of "natural born citizens" included people born to an American parent.
But the business mogul stood firm, noting that a Harvard law scholar had raised doubts and Mr Cruz could face lawsuits by Democrats wishing to challenge his qualification.

 
 Huckabee, Fiorina and Santorum took part in an undercard debate

Mr Cruz has been on the defensive over a New York Times revelation that he took a large loan from Goldman Sachs - where his wife works as a managing director - during his 2012 campaign for election to the US Senate.
At the time, he maintained the campaign was financed by he and his wife's personal assets, and the loan was not disclosed on routine campaign finance reports.
Officials from his current campaign are labelling the loan's absence from the required documents as a "mistake".
A so-called undercard debate featured businesswoman Carly Fiorina, former Arkansas Governor Mike Huckabee and former Senator Rick Santorum, who have all performed poorly in recent polls.
Kentucky Senator Rand Paul elected not to participate in the undercard debate.