In a message urging solidarity, Prime Minister Scott Morrison paid tribute to the lives lost on the 20th anniversary of the September 11 terrorism attacks.
He said Australia is one of the first countries in the world to mark the occasion and tragedy of the 2,977 deaths, including 10 Australians.
"We recall exactly where we were at the time, what we were doing and the shock that we felt when the foundations of our very world seem to shake," he said in a pre-recorded message.
"On this anniversary, we honour the 2,977 souls, people who lost their lives on that day. Our hearts go out to the 10 Australians who were among them and the many other Australians who were affected and traumatised by those events.
"So on this anniversary let our first thoughts be with them as we send our sincere condolences as a nation for the terrible loss they have suffered.
"To President Biden and all the people of the United States, we are with you today."
The Prime Minister also acknowledged the 41 Australians who died in the subsequent war in Afghanistan, saying they fought for freedom.
"We supported a US-led operation to hunt down Osama bin Laden and eliminate the capacity to stage more attacks on the West from Afghanistan."
"Sadly the fruits from that seed of hope are now very uncertain, but let us never doubt that our cause was, and will always be, a just one."
From India, Foreign Minister Marise Payne echoed that sentiment. She will soon travel to the United States with Defence Minister Peter Dutton as part of a .
"We live in a different world as a consequence of those attacks. Most immediately, there is the pain for the families who lost loved ones that day," the minister said.
"To our friends in the United States, we share your grief on this day and we stand with you against terrorism as resolutely as we did in the immediate aftermath of the attacks.
"Australia condemns terrorism and violent extremism in all its forms."
Opposition leader Anthony Albanese reflected on the moment he watched the twin towers fall on television for the first time.
"My son had just been born … I remember watching the events unfold on the TV that night, as it became clear that this wasn’t just an accident, that is was a terrorist attack."
"I remember going up and looking at my young son, as a baby, and wondering what this all meant.
"We honour those who were killed, we honour those who were wounded, we honour those who were never found, we honour those who lost their loved ones that day."
