Australian political leaders have united to offer support to the gay community following a gunman's attack on a Florida nightclub in which 50 people died.
Prime Minister Malcolm Turnbull said the attack was directed by a "murderous hatred of gay people".
"This is a vile attack on freedom ... an attack on every single one of us," Mr Turnbull told reporters.
The prime minister said he offered condolences to US ambassador John Berry, who has friends in Florida whose safety is yet to be confirmed.
Opposition Leader Bill Shorten also offered his condolences, extending his sympathy to people in the LGBTQI community.
"It was an attack on the right to be proud of who you are and who you love," Mr Shorten said.
Greens leader Richard Di Natale added his sympathies: "Violence and hate have no place in our communities and now more than ever we must stand together against these hateful acts."
Adding to the support were vigils in Sydney, where hundreds gathered on Monday night with candles and rainbow flags in remembrance of the victims.
Tony Abbott's sister Christine Forster and her partner Virginia held hands as they joined others who surrounded a nature strip at Taylor Square that was covered in flowers, rainbow flags and the word "Orlando" spelled out by candles.
Entertainer Shauna Jensen told AAP she felt heartbroken for the victims and their families.
"They just wanted to f***ing dance," she said while wiping away tears.
Lachlan Bellach, 26, from Surry Hills, said the vigil was a way for the community to show strength together.
"I hope it sends a powerful message to victims and their families during this time of grief," he told AAP.
The Department of Foreign Affairs has said it doesn't know of any Australians caught up in the massacre - which is America's deadliest mass shooting in modern history.
Former deputy prime minister Tim Fischer called on America to tighten its gun control.
"This is the agony of America, today in failing to fix dysfunctional gun laws due to the lock of the National Rifle Association on the US congress," he told AAP on Monday.
"They now must get their gun laws sorted, or otherwise expect more massacres."
Gun Control Australia called on federal Justice Minister Michael Keenan to prevent further erosion of Australia's gun laws and ban the Adler lever action shotgun.
The gun law reform organisation says political pressure from the well-financed gun lobby has led to the weakening of state and territory laws since the 1996 National Firearms Agreement.
"We're now in a position where high-powered weapons are being imported under low-powered licenses," GCA chair Samantha Lee said in a statement on Monday.
Meanwhile, the rainbow flag flew at half mast above Sydney Town Hall in solidarity with Florida's LGBTQI community and the Harbour Bridge was lit up in rainbow colours.
In Canberra, the Greens cancelled a Queen's birthday cake-eating stunt at Parliament House planned as part of a push to make Australia a republic.
