(CNN) The mass shooting at a gay nightclub in Orlando, Florida, has prompted an outpouring of sympathy across the globe, with people unfurling rainbow flags and holding vigils in tribute to the victims.

Many of the most passionate reactions to the deadly attack have come from gay social media users.

In a flurry of posts, gay people around the world have shared pictures of themselves posing, kissing and holding their partners' hands in a celebration of their sexuality, using the hashtag #GaysBreakTheInternet.

The worst mass shooting in U.S. history, which left at least 49 people dead and more than 50 wounded, has been described as both a terror attack and a hate crime by leaders and experts.

In a riposte to the attack, Twitter user @norlicious of Sweden posted pictures of herself kissing other women, saying "because our rights aren't a debate issue."

#gaysbreaktheinternet because our rights aren't a debate issue. because we exist. because we are important 💓 pic.twitter.com/MwWYlIPXD3 — norlicious (@norliciouss) 13 June 2016

Instagram user epyloniana from Germany posted a picture of herself and another woman wearing pink tank tops with "legalize gay" across them.

#loveislove #lovewins #samelove #westandwithorlando #gaysbreaktheinternet #heretostay A photo posted by aurora (@epyloniana) on Jun 12, 2016 at 9:58pm PDT

Others used #LoveWins and #OrlandoStrong to show their support.

So in support of the recent tragic events, the mass shooting in Orlando ❤️ #gaysbreaktheinternet #gay #lovewins #loveislove A photo posted by Super Gay • Norway • Marina (@otaku_erection) on Jun 13, 2016 at 5:06am PDT

'We're queer, we will not live in fear'

A massive crowd gathered Monday outside London's the Admiral Duncan pub, one of the city's best-known gay bars, which was the site of a bomb attack in 1999. Three people died and scores were wounded when neo-Nazi David Copeland detonated a nail bomb in a sports bag.

A better pic of the #lovewins banner at Soho's vigil for the victims of the #OrlandoShooting attack on the #Pulse nightclub, taken earlier this evening. #soho #london A photo posted by Bryony Jones (@bryonysjones) on Jun 13, 2016 at 2:56pm PDT

In the packed street, people held up rainbow flags and umbrellas, bouquets of flowers and balloons to show their solidarity with victims. Banners and signs read "Love Wins," "Not afraid" and "Love Trumps Hate."

"We're here, we're queer, we will not live in fear," the crowd chanted.

A minute's silence was followed with a round of cheers and applause as helium-filled balloons in rainbow colors were released, floating off into the skies above Soho.

The London Gay Men's Chorus burst into song, serenading the crowd with renditions of "Bridge Over Troubled Water" and "Somewhere Over the Rainbow."

"There are no words to articulate the horror of what has happened to these people," said Jerzy Kierkuc-Bielinski, who was at the vigil with his partner, Don Lickley.

Labour leader Jeremy Corbyn, second from left at front, attends a vigil at the Admiral Duncan pub on Old Compton Street.

"It's all the more poignant that we're standing here with our brothers and sons, sisters and daughters outside the Admiral Duncan on Old Compton Street, which has experienced the horror of this kind of attack in the past, on people who were just meeting with friends, having fun -- just existing, not provoking."

Edwin Sesange, originally from Uganda, said the attack was a "wake-up call ... to remind us that we need to do more to change attitudes, to reach out to people." He added, "if something like this can happen as a reaction to seeing two boys kiss, then it shows more work needs to be done."

'Cancer of radicalization'

World and religious leaders were also quick to stand in solidarity with the United States, as the nation reeled from its worst terror attack since 9/11.

Omar Mateen, the U.S.-born gunman, pledged allegiance to ISIS in a 911 call during the attack.

Queen Elizabeth II, who celebrated her 90th birthday this weekend, led tributes in the UK, saying on Twitter that both she and Prince Philip were shocked by the events in Orlando.

The Queen: "Prince Philip & I have been shocked by the events in Orlando. Our thoughts & prayers are with all those who have been affected" — The Royal Family (@RoyalFamily) June 12, 2016

And British Prime Minister David Cameron said he was "horrified" by reports of the shooting.

I'm horrified by reports of the overnight shooting in Orlando. My thoughts are with the victims and their families. — David Cameron (@David_Cameron) June 12, 2016

German Chancellor Angela Merkel said in a statement to President Obama that "we are connected in deep mourning."

"But even in the face of such cruelty, we will stick to our values and beliefs ... We will not give up our freedom, our lives rooted in humanity and charity and our enjoyment of the community. Our open societies are stronger than any rabid hatred," Merkel said.

Photos: Orlando vigil for shooting victims People light candles during a vigil one day after a gunman killed 49 people at a gay nightclub, marking the deadliest mass shooting in U.S. history Hide Caption 1 of 7 Photos: Orlando vigil for shooting victims Attendees make signs with messages like "#OrlandoStrong" and "We Stand Together." Hide Caption 2 of 7 Photos: Orlando vigil for shooting victims Mourners embrace at the vigil, which took place in front of the Dr. Phillips Center for the Performing Arts in downtown Orlando. Hide Caption 3 of 7 Photos: Orlando vigil for shooting victims Family and friends of shooting victims Leroy Valentin Fernandez and Xavier Emmanuel Serrano Rosado attend the vigil. They were wearing matching "RIP Eman & Roy" shirts. Learn more about the victims Hide Caption 4 of 7 Photos: Orlando vigil for shooting victims A flower is placed on a long sheet of paper adorned with heartfelt messages. Hide Caption 5 of 7 Photos: Orlando vigil for shooting victims Thousands of people attended Monday night's vigil in Orlando. Hide Caption 6 of 7 Photos: Orlando vigil for shooting victims The crowd holds up candles during a moment of silence for the victims. Hide Caption 7 of 7

Pakistan's Prime Minister Nawaz Sharif said that shooting didn't "represent the will of a vast majority of Muslims."

"It is just another representation of a cancer of radicalization -- one that we promise to fight every day of our lives," he said in a statement.

Chinese President Xi Jinping, India's Narendra Modi, former Afghan President Hamid Karzai and Singapore President Tony Tan were among the leaders that expressed their condolences and offered sympathy to the victim's families.

Shocked at the shootout in Orlando, USA. My thoughts & prayers are with the bereaved families and the injured. — Narendra Modi (@narendramodi) June 12, 2016

Days after a terror attack in Tel Aviv, Mayor Ron Huldai tweeted an image showing City Hall lit up in rainbow colors and the colors of the U.S. flag. In Seattle, a rainbow flag flew at half-staff on the Space Needle, while the One World Trade Center in New York was among a number of U.S. buildings lit up in rainbow colors.

In solidarity with #Orlando #TelAviv City Hall is lit up with the #USA flag and the flag of the #LGBTQ community pic.twitter.com/ULKR0BeR7N — Mayor of Tel Aviv (@MayorOfTelAviv) June 12, 2016

In France, members of the lesbian and gay community gathered at an art center in downtown Paris on Sunday, placing burning candles in the shape of a heart and draping themselves in rainbow flags.

"We are here to express our solidarity with the victims and their families, with all the victims who were injured," one woman who attended the vigil told CNN affiliate BFM TV.

Photos: World reacts to Orlando attack U.S. President Barack Obama and Vice President Joe Biden place flowers at a memorial Thursday, June 16, for the victims of the nightclub shooting in Orlando. At least 49 people were killed in the massacre, the deadliest mass shooting in U.S. history. Hide Caption 1 of 34 Photos: World reacts to Orlando attack People remember the victims during a vigil at an LGBT community center in San Juan, Puerto Rico, on Tuesday, June 14. Hide Caption 2 of 34 Photos: World reacts to Orlando attack Jean Dasilva, left, is comforted by Felipe Soto as they mourn the loss of their friend Javier Jorge-Reyes on June 14. They were visiting a makeshift memorial at Pulse, the gay nightclub where the shooting took place. Hide Caption 3 of 34 Photos: World reacts to Orlando attack Britain's Prince William and his wife, Catherine, sign a book of condolences at the U.S. Embassy in London on June 14. Hide Caption 4 of 34 Photos: World reacts to Orlando attack A vigil for the Orlando victims is held in New Delhi on June 14. Hide Caption 5 of 34 Photos: World reacts to Orlando attack Thousands gather in Orlando on Monday, June 13, to pay tribute to those who were killed the day before. Hide Caption 6 of 34 Photos: World reacts to Orlando attack The Eiffel Tower in Paris is illuminated in rainbow colors on June 13. Hide Caption 7 of 34 Photos: World reacts to Orlando attack A woman lights a candle during a vigil in Sydney on June 13. Hide Caption 8 of 34 Photos: World reacts to Orlando attack Runners pass under half-staff flags at the Washington Monument on June 13. Hide Caption 9 of 34 Photos: World reacts to Orlando attack U.S. Ambassador to Thailand Glyn T. Davies, right, gestures to members of the LGBT community outside the U.S. Embassy in Bangkok, Thailand, on June 13. They were holding a vigil for the victims. Hide Caption 10 of 34 Photos: World reacts to Orlando attack Students in Mumbai, India, light candles near a rangoli, an Indian form of art created on the ground, on June 13. Hide Caption 11 of 34 Photos: World reacts to Orlando attack White roses and rainbow flags are displayed in front of the U.S. Embassy in Berlin on June 13. Hide Caption 12 of 34 Photos: World reacts to Orlando attack People gather for a vigil in Seoul, South Korea, on June 13. Hide Caption 13 of 34 Photos: World reacts to Orlando attack The city of Melbourne posted this image on its Twitter account June 13 "as a mark of respect for those touched by the attack in Orlando. Town Hall is lit in the rainbow #LoveIsLove." Hide Caption 14 of 34 Photos: World reacts to Orlando attack Mourners hold an LED sign as they march during a vigil in Dallas on Sunday, June 12. Hide Caption 15 of 34 Photos: World reacts to Orlando attack Lin-Manuel Miranda, creator of the musical "Hamilton," delivers a sonnet at the Tony Awards to pay tribute to the Orlando victims. Hide Caption 16 of 34 Photos: World reacts to Orlando attack A rainbow flag flies at half-staff on the Space Needle in Seattle on June 12. Hide Caption 17 of 34 Photos: World reacts to Orlando attack Henry Duong pays tribute during a memorial service in San Diego. Hide Caption 18 of 34 Photos: World reacts to Orlando attack One World Trade Center is lit in rainbow colors June 12 in New York. Hide Caption 19 of 34 Photos: World reacts to Orlando attack Mourners hold up signs during a vigil in Washington on June 12. Hide Caption 20 of 34 Photos: World reacts to Orlando attack Mourners gather during a vigil in front of the White House on June 12. President Barack Obama called the mass shooting an "act of terror" in remarks to the nation. Hide Caption 21 of 34 Photos: World reacts to Orlando attack Two women light candles during a vigil in front of the U.S. Embassy in Santiago, Chile, on June 12. Hide Caption 22 of 34 Photos: World reacts to Orlando attack Mourners observe a moment of silence during a vigil in Atlanta. Hide Caption 23 of 34 Photos: World reacts to Orlando attack Ryan Gibson, left, embraces Tabor Winstead during a vigil in Raleigh, North Carolina, on June 12. Hide Caption 24 of 34 Photos: World reacts to Orlando attack A man injured in the attack stands with other mourners as they attend a memorial service at an Orlando church. Hide Caption 25 of 34 Photos: World reacts to Orlando attack Participants in the Los Angeles gay pride parade show their support for the victims on June 12. Hide Caption 26 of 34 Photos: World reacts to Orlando attack People hold candles near Rome's Colosseum as they take part in a ceremony on June 12. Hide Caption 27 of 34 Photos: World reacts to Orlando attack A man places a handprint on a makeshift memorial near the nightclub where the attack took place. Hide Caption 28 of 34 Photos: World reacts to Orlando attack People gather for a vigil June 12 outside the Stonewall Inn in New York. Stonewall is considered the birthplace of the gay rights movement. Hide Caption 29 of 34 Photos: World reacts to Orlando attack People gather in Sao Paulo, Brazil, to mourn the Orlando victims on June 12. Hide Caption 30 of 34 Photos: World reacts to Orlando attack People gather for a vigil near the Beaubourg art center in Paris on June 12. Hide Caption 31 of 34 Photos: World reacts to Orlando attack People line up to donate blood at a blood bank in Orlando. Hide Caption 32 of 34 Photos: World reacts to Orlando attack People show their support for Orlando during the Los Angeles gay pride parade. Hide Caption 33 of 34 Photos: World reacts to Orlando attack The Rev. Jeffrey Montoya leads a prayer in Greenfield, Wisconsin, on June 12. Hide Caption 34 of 34

"We have a lot of solidarity as well as a lot of sadness."

The attack took place during Pride month -- "a time of joy and celebration" for the gay and lesbian community -- said the International Lesbian, Gay, Bisexual, Trans and Intersex association ( ILGA ), which advocates for equal rights and represents 1,100 groups worldwide.

"It is hard not to fear that this was a targeted attack against a community, and this is a dreadful reminder of the price far too many LGBTIQ persons, all around the world, have to pay simply for being who they are," the ILGA said in a statement.

In China, 51 LGBT groups issued a collective statement expressing "condolences, solidarity and love." Blued, China's largest gay dating app, changed its loading screen to honor the Orlando shooting victims.

Gay and lesbian groups planned a candlelight vigil for Monday evening in Seoul, the capital of South Korea.

Blued, China's largest gay dating app, changed its loading screen in the wake of the Orlando shooting.

Pope's 'horror'

In unusually vivid language, the Vatican said Sunday that Pope Francis reacted in "horror" and "condemnation" after learning of the nightclub massacre.

"We all hope that ways may be found, as soon as possible, to effectively identify and contrast the causes of such terrible and absurd violence which so deeply upsets the desire for peace of the American people and of the whole of humanity," the Holy See Press Office said in a statement.

Australian Prime Minister Malcolm Turnbull offered condolences to the bereaved and sought to reassure his own countrymen and women, saying that Australian intelligence and security agencies "had the tools" they need to keep people safe.

"We are rigorous in our efforts to ensure that guns are not illegally imported into Australia and that our strong gun control laws are strictly enforced," Turnbull said.

From Sydney, Australia, Twitter user @sethdarby posted a picture of a vigil from Taylor Square, the heart of the city's gay community and nightlife.

The Sydney Harbor Bridge was lit up in rainbow colors, while Australians in Melbourne also attended vigils.

"I just feel incredibly sad about what has happened," one woman told CNN affiliate Sky News Australia in Melbourne. "I was meant to be going into work and I thought, nah, I need to come here and spend time with my community."