The nation and LGBT communities were in stunned mourning as the toll from a massacre early Sunday at a gay nightclub in Orlando, Fla., rose to 50 dead and 53 wounded, making it the worst mass shooting in U.S. history.

The gunman, identied as Omar Mir Seddique Mateen, 29, was shot and killed in a gunbattle with police after shooting his way into the club, Pulse, then going on a killing spree with a semiautomatic rifle and handgun.

Mateen reportedly was born in New York to Afghan immigrants. In a 911 call, Mateen pledged his allegiance to ISIS, the militant Islamists that have overrun parts of Syria and Iraq, and, according to his father, detests homosexuals. 

In a nationally televised speech Sunday afternoon, President Barack Obama labeled the attack an "act of terror and an act of hate."

“We know enough to say this was an act of terror and an act of hate,” Obama said. “The FBI is appropriately investigating this as an act of terror. We will go wherever the facts lead us. What is clear is he was a person filled with hatred.

"This massacre is therefore a further reminder of how easy it is for someone to get their hands on a weapon that lets them shoot people in a school, or in a house of worship, or a movie theater, or in a nightclub," Obama said. And we have to decide if that’s the kind of country we want to be. And to actively do nothing is a decision as well."

As the names of victims began to be released, gay clubs organized vigils, while police stepped up security at Pride events and New York officials ordered flags struck to half staff in honor of the dead.

New York

The NYPD issued assurances that it can safeguard the city's Pride events culminating in the annual parade Sunday June 26.

"The NYPD is always in a state of vigilance and  our anti-terror capacity will ensure a safe upcoming Pride week," the department said in a tweet.

The city’s gay clubs will also be adding security in the wake of the mass shooting in Orlando.

"We have been contacted by the Police Department and have been told that there is no intel involving a correlated terrorist attack of any kind, but we have been asked to remain very aware of our surroundings and report anything suspicious if we see it," said James Wells, bar manager at Therapy nightclub in Hell's Kitchen.

Clubs throughout the city offered condolences to the victims and their families and organized vigils and memorials.

The Stonewall Inn, famously known as the site of the 1969 Stonewall Riots that many consider the birth of the gay rights movement, planned to hold a vigil Sunday night organized by the Stonewall Democrats.

"Our thoughts and prayers are with the victims and families in Orlando. We stand in solidarity and in sadness with our entire LGBT community," the organizers posted.

Other vigils planned Sunday night included a gathering at Diversity Plaza in Jackson Heights with Muslim and LGBT activists to "to denounce violence in all its forms and pay their respects to the victims of the Orlando terror attack,"  and an interfaith vigil at Harlem's Judson Church.

The cast of the Broadway musical "Hamilton" announced that it would be performing at the Tony awards Sunday night without its prop guns because of the shooting.

New York Mayor Bill de Blasio and Gov. Andrew Cuomo ordered flags in the city and state to be flown at half-staff in remembrance of the 50 victims.

Boston

Security was increased for Sunday's Pride events as news spread of the massacre in Orlando.

"When we woke up and read the news, we were horrified," Pride President Sylvain Bruni said. "The fact that a gay venue was targeted, whether that was specifically the motive or not, goes to our hearts because we are celebrating Pride right now."

Boston Police Commissioner William Evans said earlier Sunday that his department would be providing additional support to LGBT clubs in the city.

"Clearly this was a hate crime geared at the gay population, and we’re going to make sure they are safe,” Evans told reporters.

Bruni urged the LGBT community not to be deterred by the shooting.

"We are not afraid," he said. "We should be having a celebration of pride and who we are. The city has our back. The city has stepped up greatly."

David Goulart, 44, of Quincy, said the LGBT community has stood together through challenging times in its history.

"I don't think the gay community has ever been the community to sit back and live in fear," he said. "We're just not that kind of group."

Philadelphia

Philly’s Pride Day parade was underway as the full horror of what had occurred in Orlando became apparent. Revelers marched through the Gayborhood and Old City Sunday, but the day’s festivities were tinged with sorrow.

"The hearts of the staff, management and owners of Woody's along with Philly's LGBTQ community are heavy this morning," Woody's wrote on their Facebook page. "Our prayers and thoughts go out to our LGBTQ brothers and sisters in Orlando Florida. Love will always prevail."

Voyeur Nightclub echoed that statement, writing " We join our LGBTQ family at Woody's in praying for our LGBTQ brothers and sisters in Orlando Florida today."

Philadelphia director of LGBT affairs Nelli Fitzpatrick wrote on Facebook that police were increasing their presence at the Pride parade, but had no reports of any threats of violence.

"They have no reason to believe that there are any similar threats for today's Philly Pride events," Fitzpatrick wrote in the post. "However, [Philadelphia Police Department] will be taking all necessary precautions for today's parade and festival to ensure a safe event for everyone."

A vigil for the victims is planned outside City Hall at 6:30 p.m. Monday.

"I'm horrified," said Chichi Lovett, 64, visiting Philly from New York, who said she wasn't sure if it added to an increased sense of danger. "The terrorism has been going on for a while, against us and the gay community."

Lovett linked the violence to Donald Trump's presidential campaign. "His inflammatory stances are just going to fan the flames of everybody else. ... The climate has let all the craziness out of the box."​