Prime Minister Scott Morrison has described a deadly Islamic terror attack in France as disgusting and cowardly.
A knife-wielding extremist has beheaded a woman and killed two other people at a church in the city of Nice.
Attacks also took place in the southern French city of Avignon and at the French consulate in Saudi Arabia.
"These multiple attacks are despicable. They are disgraceful," Mr Morrison told reporters on Friday.
"Not only are they an attack on the individuals and their families but they are an attack on liberty. When we think of France we think of liberty. And we stand with the people of France."
Mr Morrison exchanged text messages with French President Emmanuel Macron overnight.
Mr Macron responded: "We will win."
"We stand with France in that declaration," the prime minister said.
"Free people all around the world will stand together to defend freedom, to defend our liberties and to stand against the evil terror that seeks to assault that."
Mr Morrison said the attacks were an awful reminder of evil lurking in the shadows.
"Our prayers are for the victims and their families. Our thoughts are with all the people of France wherever they are," he said.
"We stand with president Macron and the government of France as they do all in their power to stamp out this terrible evil that has struck their country."
Opposition Leader Anthony Albanese described the terror attack as horrific and barbaric.
"It will produce a real shock wave through France. It won't blunt the French values of liberty, equality and fraternity. And all Australians stand with them today," he told reporters.
Most leaders around the world have condemned the attack, which was reportedly carried out by a 21-year-old Tunisian migrant who recently entered France from Italy.
Within hours of the Nice attack, police killed a man who threatened passers-by with a handgun near Avignon.
In Saudi Arabia, a man was arrested after attacking and injuring a guard at the French consulate in Jeddah.
Home Affairs Minister Peter Dutton said the attacks were proof of an escalating terror threat around the world.
"It's clear that over COVID these people just haven't gone away," he said.
"They're still spreading messages of hate over the internet, indoctrinating young people, even here."
ASIO director-general Mike Burgess told a parliamentary committee he was horrified by the latest act of calculated, premeditated murder in France.
"Attacks such as this, targeting some of society's most innocent, causes my officers at all levels, both here in Australia and overseas, to redouble our focus and our effort to counter this menacing threat," he said.
Mr Dutton indicated domestic security agencies recently executed warrants in relation to terror activity, which have not yet been made public.
"Clearly the threat is still as relevant to us as it has ever been. It's a major concern and as a western nation we're still well and truly under threat," he said.
"These people would seek to do us harm in a heartbeat if they could and ASIO and the AFP and the state agencies do a great job."