A gunman killed 50 people and left 53 injured in a crowded Orlando gay nightclub in what marks the worst mass shooting in American history on Sunday (June 12), one that law enforcement officials are calling an act of terrorism.

Music Stars React to Orlando Nightclub Massacre, Deadliest Mass Shooting in U.S. History

The shooter, who has been identified as Omar Mir Seddique Mateen, stormed the popular Pulse nightclub wielding an assault-type rifle and a handgun, opening fire on the crowd before dying in a gunfight with SWAT officers, police said on Sunday morning.

In the wake of the horrific event, which occurred during Pride month and hours before Pride parades were to kickoff throughout the country, many looked to see the reactions of the Democratic and GOP presumptive presidential nominees.

Shooting At Orlando Nightclub Leaves 50 Dead in Largest Mass Shooting in U.S. History

Hillary Clinton took to Twitter to say, "Woke up to hear the devastating news from FL. As we wait for more information, my thoughts are with those affected by this horrific act."

Woke up to hear the devastating news from FL. As we wait for more information, my thoughts are with those affected by this horrific act. -H — Hillary Clinton (@HillaryClinton) June 12, 2016

Donald Trump also woke up to the news, and continued to tweet throughout the morning.

Really bad shooting in Orlando. Police investigating possible terrorism. Many people dead and wounded. — Donald J. Trump (@realDonaldTrump) June 12, 2016

Horrific incident in FL. Praying for all the victims & their families. When will this stop? When will we get tough, smart & vigilant? — Donald J. Trump (@realDonaldTrump) June 12, 2016

But it was his tweet referencing "congrats" over being "right on radical Islamic terrorism" that caused a swift reaction on social media, with many questioning how Trump would handle such a massacre if he were indeed elected president of the United States.

Appreciate the congrats for being right on radical Islamic terrorism, I don't want congrats, I want toughness & vigilance. We must be smart! — Donald J. Trump (@realDonaldTrump) June 12, 2016

Throughout their morning coverage, CNN questioned Trump's continual tweeting as the news developed, and others, such as George Takei, John Legend and Eric Stonestreet, criticized Trump's handling of the situation.

Once again, Donald, you have shown why you cannot lead us. 50 people are dead, and you bask in congratulations. https://t.co/pUN7ceAff7 — George Takei (@GeorgeTakei) June 12, 2016

Forget presidential, this isn't even a vaguely human way to react to a tragedy. His devotion to ego is infuriating. https://t.co/L8bmrynuCb — Rou Reynolds (@RouReynolds) June 12, 2016

Trump is truly an awful person. https://t.co/vQp3CQ9Nmv — John Legend (@johnlegend) June 12, 2016

Is this the grossest tweet in Twitter history? Yes. I think it is. https://t.co/G8W6UlMyM0 — Eric Stonestreet (@ericstonestreet) June 12, 2016

Dear Mr Trump. I'm not sure that today is a day for any kind of congrats and jelly and ice cream. https://t.co/QTaVYe7TJo — Adil Ray (@adilray) June 12, 2016

.@realDonaldTrump You're congratulating yourself because 50 people are dead this morning in a horrific tragedy? — Meghan McCain (@MeghanMcCain) June 12, 2016

President Obama addressed the nation on Sunday, saying the White House is working with the FBI and national security to investigate the shooting. He called the shooting "the most deadly shooting in American history."

As Obama began his address, Trump again took to twitter.

Is President Obama going to finally mention the words radical Islamic terrorism? If he doesn't he should immediately resign in disgrace! — Donald J. Trump (@realDonaldTrump) June 12, 2016

On Sunday afternoon, Clinton released a statement seconding Obama's earlier statements, calling the events an "act of terror" and also "an act of hate."

"This was an act of terror. ... This was also an act of hate." —Hillary on the attack in Orlando https://t.co/MmaGjrSufr — Hillary Clinton (@HillaryClinton) June 12, 2016

Trump has yet to release an official statement. Read Clinton's full statement, which she shared via her Twitter account, below:

I join Americans in praying for the victims of the attack in Orlando, their families and the first responders who did everything they could to save lives.

This was an act of terror. Law enforcement and intelligence agencies are hard at work, and we will learn more in the hours and days ahead. For now, we can say for certain that we need to redouble our efforts to defend our country from threats at home and abroad. That means defeating international terror groups, working with allies and partners to go after them wherever they are, countering their attempts to recruit people here and everywhere, and hardening our defenses at home. It also means refusing to be intimidated and staying true to our values.

This was also an act of hate. The gunman attacked an LGBT nightclub during Pride Month. To the LGBT community: please know that you have millions of allies across our country. I am one of them. We will keep fighting for your right to live freely, openly and without fear. Hate has absolutely no place in America.

Finally, we need to keep guns like the ones used last night out of the hands of terrorists or other violent criminals. This is the deadliest mass shooting in the history of the United States and it reminds us once more that weapons of war have no place on our streets.

This is a time to stand together and resolve to do everything we can to defend our communities and country.

Clinton continued to tweet after releasing her statement.

"To the LGBT community: please know that you have millions of allies across our country. I am one of them.” —Hillary https://t.co/MmaGjrSufr — Hillary Clinton (@HillaryClinton) June 12, 2016

"We need to keep guns like the ones used last night out of the hands of terrorists or other violent criminals." —Hillary on the FL attack — Hillary Clinton (@HillaryClinton) June 12, 2016

This article originally appeared in THR.com.

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