"As is the case virtually every day, Donald Trump is showing the American people that he is a pathological liar. Obviously, while I appreciate that we had supporters at Trump's rally in Chicago, our campaign did not organize the protests.
"What caused the protests at Trump's rally is a candidate that has promoted hatred and division against Latinos, Muslims, women, and people with disabilities, and his birther attacks against the legitimacy of President Obama.
"When that is what the Trump campaign is doing, we should not be surprised that there is a response.
"What Donald Trump must do now is stop provoking violence and make it clear to his supporters that people who attend his rallies or protest should not be assaulted, should not be punched, should not be kicked. In America people have a right to attend a political rally without fear of physical harm."