Clinton takes aim at native New Yorker Trump in TV ad
Hillary Clinton has taken aim at Donald Trump's hardline immigration policies as well as violent incidents at some of his rallies in a new television ad campaign set to run in New York.
Democratic hopeful Mrs Clinton claims in the ad that while some people say America's problems can be solved by "building walls" and "banning people based on their religion", New Yorkers know better.
The TV spot shows a clip of a man being punched at a recent Trump rally and briefly flashes a sign from one of the billionaire's new hotels.
New York holds its Democratic and Republican primaries on April 19.
While Mrs Clinton still faces a strong challenge from Democratic rival Bernie Sanders, it is notable that the ad focuses on Mr Trump, the Republican frontrunner and a native New Yorker.
Meanwhile, none of the three Republican presidential candidates have committed to support whoever the party chooses to fight the election later this year.
This contradicts the stance that Donald Trump, Ted Cruz and John Kasich took early in the campaign, when they agreed they would back the party's eventual choice.
The three were asked this question again on Tuesday night in town hall appearances in Milwaukee, hosted by CNN.
Mr Trump, who is the front-runner, replied: "We'll see who it is."
Mr Cruz said: "I'm not in the habit of supporting someone who attacks my wife and children."
Similarly, Mr Kasich said: "I will wait and see what happens."
Wisconsin's April 5 primary looks pivotal in the Republican race.
If Mr Cruz wins, it would narrow Donald Trump's already tight path to the nomination and raise the prospect of a contested party convention.
Delegates there might turn to other candidates if the billionaire fails to win on the first ballot.
Mr Trump arrived in Wisconsin fending off another controversy after campaign manager, Corey Lewandowski, was charged with misdemeanour battery in Florida over an altercation with a female reporter earlier this month.
Mr Cruz has picked up support from Wisconsin governor Scott Walker, a former Republican presidential contender.
Mr Trump heads into Wisconsin with 739 delegates to Mr Cruz's 465, while Mr Kasich lags behind with 143.
Wisconsin has 42 Republican delegates, with 18 going to the state-wide winner and 24 divided among the winners in each of the state's eight congressional districts.
Mr Trump told supporters at a rally that "if we win Wisconsin, it's pretty much over," noting his significant delegate lead over both his rivals.
He would need 1,237 delegates by the end of the primary season to capture the nomination and avoid a contested convention.
Among the Democrats, based on primaries and caucuses to date, Mrs Clinton has 1,243 delegates to Bernie Sanders' 975.
Including superdelegates - party leaders who are free to support any candidate - Mrs Clinton has 1,712 delegates to Mr Sanders' 1,004, leaving her shy of the 2,383 it takes to win the nomination.
After sweeping three western state primaries over the weekend, Mr Sanders is hoping to trim Mrs Clinton's commanding lead in the delegate count and claim momentum with a victory in Wisconsin.
Meanwhile, police are looking for a man who pepper-sprayed a 15-year-old girl as opponents and supporters of Mr Trump clashed outside a Wisconsin rally.
The altercation is the latest in a series of confrontations that have marred recent events in the Trump campaign.
The girl told police she punched a man who groped her, and another man then pepper-sprayed her, Janesville Police Sgt Aaron Ellis said.
The girl and a 19-year-old woman standing next to her were treated and released from a hospital.
Sgt Ellis said the girl could face charges for punching the man, identified by the Wisconsin State Journal as Dan Crandall.
"I didn't touch her," Mr Crandall told the newspaper.
"She started to challenge why I was at the Trump rally since I was a grown man. I told her I was at the Trump rally because I was a grown man and I cared about my country."
Mr Crandall said someone standing behind him used the pepper spray. That person could be charged with illegal discharge of pepper spray since he was not using it in self-defence, Sgt Ellis said.
"It doesn't appear that he was directly involved," he said.