By Emily Flitter and Fiona Ortiz
Donald Trump's Republican rivals have condemned protests that shut down his planned Chicago rally, but added that his incendiary speeches were partly to blame.
In statements to the press, candidates Ted Cruz and Marco Rubio both called the incident "sad" and said the people who chanted anti-Trump slogans and scuffled with Trump's fans inside a stadium at the University of Illinois should have respected the candidate and let the rally happen.
But they added that Trump shared some responsibility.
Trump has drawn fervent support as well as harsh criticism for his calls to build a wall along the US-Mexico border and to impose a temporary ban on Muslims entering the country.
His rallies often attract small groups of protesters, but Friday's was the first at which there may have been as many protesters as supporters.
The two sides shouted at each other until a Trump campaign staffer appeared and announced the event would be put off until an unspecified date for security reasons. The cancellation followed a an appearance by Trump in St Louis, Missouri earlier on Friday during which protests forced the front-runner to halt his speech repeatedly.
"Go home to mommy," Trump said as security personnel ejected one of the protesters in St. Louis.
"When you have a campaign that affirmatively encourages violence," Cruz, the Texas senator, said, "you create an environment that only encourages this sort of nasty discourse."
In Chicago, while activity inside the rally was largely peaceful, a group of protesters gathered nearby clashed briefly with police when they tried to shut down an expressway, a Chicago Police Department spokesman said.
Two police officers were injured; one required stitches, according to the spokesman. A reporter for CBS News was arrested and later released, according to media reports.
Trump has a significant lead in primary contests over the three remaining Republicans vying for the White House, and he is looking to cement it on Tuesday when voters in five more states, including Illinois, go to the polls.
Ohio Governor John Kasich, also battling Trump for the Republican presidential nomination, said the protests occurred because "the seeds of division that Donald Trump has been sowing this whole campaign finally bore fruit."
Rubio, the Florida senator, had the harshest words for the protesters. He said in a Fox News interview protests in Chicago had become "an industry" and some of the people involved were "probably being paid to do this."