Orlando shooting: Trump says 'was right about radical Islamic extremists'

In the wake of the mass shooting at a gay nightclub in Orlando, the deadliest mass shooting in the United States since 9/11, presumptive GOP presidential nominee Donald Trump has said that he was "right" about warning about the danger of radical Islamic extremists.

"Appreciate the congrats for being right on radical Islamic terrorism, I don't want congrats, I want toughness & vigilance. We must be smart!," he tweeted.

Trump has in the past called for a ban on the Muslims from entering the U.S. and the destruction of ISIS.

He also called on President Barack Obama to take a stand against"radical Islamic terrorism" or else "resign in disgrace" after a mass shooting claimed 50 lives.

Hillary Clinton, the presumptive Democratic presidential candidate, also condemned the terror attack.

"We need to redouble our efforts to defend our country from threats at home and abroad," she said focusing on the threat of terrorism.

Clinton also called more stringent restrictions on guns.

Condemning the attack, President Obama called the shooting an "act of terror" that served as a "sobering reminder that attacks on any American, regardless of race, ethnicity, religion or sexual orientation is an attack on all of us."

"No act of hate or terror will ever change who we are or the values that make us Americans," he added from the White House briefing room.

Mateen, 29, an American-born man who'd pledged allegiance to ISIS gunned down 50 people early Sunday at a gay nightclub in Orlando.

According to a U.S. official, Mateen called 911 during the attack to pledge allegiance to ISIS and mentioned the Boston Marathon bombers, reports CNN.