Striking at the heart of Britain.
That is British Prime Minister Theresa May's description of the attack in London, a city she says is a city for all nationalities, religions and cultures.
It is a city, she says, that celebrates the values of liberty, democracy and freedom of speech.
Ms May says the area near the British parliament was targeted for a reason but such people will continue to fail in their objective.
"Let me make it clear today, as I have had cause to do before: Any attempt to defeat those values through violence and terror is doomed to failure."
No Australians are believed to have been killed or injured in the attack.
But Prime Minister Malcolm Turnbull says Australia stands in solidarity with the people of Britain and the police presence at Parliament House in Canberra will now be increased.
He says the attack is also a reminder of the risk police forces, intelligence services and the men and women of the Australian Defence Force face every day in protecting the nation.
Mr Turnbull is urging Australians to remain confident in their country's counterterrorism measures.
"We will never let them intimidate us or challenge our democratic way of life, or the freedoms for which generations of Australians have served and died to keep secure. The challenge that we face here in Australia is, as I said, a very real one, but we have the finest security agencies in the world."
Security agencies have reportedly disrupted 12 planned attacks on Australian soil since September 2014.
But Foreign Minister Julie Bishop, attending international talks in Washington on the fight against the self-proclaimed Islamic State, admits it is hard to detect individual, or so-called lone wolf, attacks.
She notes, without jumping to conclusions, the use of a vehicle in the London attack is similar to attacks inspired by IS, or ISIS, in Brussels, Paris and Nice
"It certainly has the hallmarks of some of the recent ISIS-inspired terrorist attacks that we have seen elsewhere, but it's too early for any conclusion to made on that point."
United States president Donald Trump, in a call to Theresa May, has offered his condolences and pledged the full cooperation and support of the US government.
White House spokesman Sean Spicer has reiterated the President's message.
"We applaud the quick response that the British police and their first responders made to the situation. The victims in this are in our thoughts and our prayers. The city of London and Her Majesty's government have the full support of the US government in responding to the attack and bringing to justice those who are responsible."
Three French schoolchildren were hurt in the attack.
French president Francois Hollande says France, which has been hit hard by such attacks, knows what the British people are experiencing.
He says Europe must do more to counter the threat.
"We must provide all the conditions to respond to these attacks, which is what we've been doing for several months here in France and what I've been calling for on the European front. We can clearly see that, on the European level and beyond that, we have to organise ourselves."
The attack came on the same day European Union officials were commemorating the first anniversary of the bombings at Brussels' Zaventem Airport and Maelbeek metro station.
Those attacks killed 32 people and wounded hundreds.
European Commission president Jean-Claude Juncker was at a memorial service for those killed in Brussels when he heard what had happened in London.
So, Im really highly emotional today. And the fact that, exactly the same day, something similar happened in London and to London is really putting me in a situation of someone who has a language that doesn t have the words enough to express what Im deeply feeling.
Britain is on its second-highest alert level of "severe," meaning an attack by militants is considered highly likely.
Australia's terrorism threat level remains at "probable," and the Department of Foreign Affairs and Trade advises Australians in Britain to "exercise normal safety precautions."
