"Really bad shooting in Orlando. Police investigating possible terrorism. Many people dead and wounded."
But his second tweet, an hour and a half later, was not so measured as he returned to campaign trail politics.
Then he posted a sympathetic tweet about the Orlando tragedy, followed by one in which he took credit for "being right on radical Islamic terrorism."
And then the billionaire businessman went on the offensive, saying, "Is President Obama going to finally mention the words radical Islamic terrorism? If he doesn't he should immediately resign in disgrace!"
On the other hand, Trump's rival and presumptive Democratic nominee Hillary Clinton first tweeted a note of concern for the victims and after few hours she issued a statement trying to address the main issues which were highlighted by the attack - terrorism, gay rights and gun control.
Trump's brash attitude has helped him so far in Republican primaries. His standing improved after the shootings in San Bernardino, Calif., and his call for "a total and complete ban" on all Muslims entering the United States. But it remains to be seen whether the much larger general-election audience will react as favorably to a candidate who has called for "a hell of a lot worse" than waterboarding, has said of terrorists that "you have to take out their families."
Trump issued a formal statement on Sunday afternoon but before that he had already made most of his points about the attack via Twitter. At one point on Sunday, Trump, who has nearly 9 million followers, tweeted, "Reporting that Orlando killer shouted 'Allah hu Akbar!' as he slaughtered clubgoers."