'Horrific': Hillary Clinton and Donald Trump react to Orlando shooting
Clinton and Trump both took to Twitter to acknowledge the shooting.
The presumptive Republican presidential nominee highlighted a potential connection to terrorism. Authorities have said the incident is being investigated as an act of terror.
Clinton expressed her condolences for the victims, tweeting out the message in English and in Spanish.
In an interview on "Meet The Press," Sen. Bernie Sanders also weighed in, expressing his sympathy for the victims and calling for stricter gun-control laws.
"It's horrific, it's unthinkable, and my hopes go out to all those who were shot that they can recover," Sanders said. "And I've got to tell you, 25 years ago, I believe that in this country, we should not be selling automatic weapons which are designed to kill people. We have got to do everything that we can on top of that to make sure that guns do not fall into the hands of people who should not have them, criminals, people who are mentally ill."