President Obama, visibly shaken, made a brief statement following Sunday's deadly shooting as the White House lowered flags to half-staff. The president sent prayers to the victims' families and the people of Orlando after an "act of terror and an act of hate."
The presumptive Democratic presidential nominee, Hillary Clinton, said that her "thoughts are with those affected by this horrific act" in a tweet.
Donald Trump, the presumptive Republican presidential nominee, was one of the first politicians to react amid claims that the attacks were terrorism. He wrote a series of tweets asking when America will get "tough, smart & vigilant."
Florida Sen. Marco Rubio tweeted about the need for blood donations for survivors.
A Vatican spokesperson told The Associated Press that Pope Francis expressed "deepest feelings of horror and condemnation" over what he called "homicidal folly and senseless hatred." The pope also asked for "prayer and compassion" for the victims and their families.
LGBT activist Stuart Milk, nephew of Harvey Milk, shared a statement on social media, sending "a world of love and prayers to all those who are grieving today."
Ellen Degeneres was one of many celebrities who shared their sorrow on social media.
Other celebrities called for change, specifically tougher gun restrictions.
In one week: our hearts break for Christina Grimmie and her family, her fans. Our hearts break for the queer community in Orlando, unsafe even in a space they created for themselves. Our hearts break for a country where this is what the news looks like day after day. The concerned citizens of the United States of America demand change.