Witnesses of Friday's London Bridge terrorist attack have described how one bystander deployed an unlikely weapon to help bring an end to the deadly incident.
A "hero" bystander used a 1.5 metre narwhal tusk to fight off the London Bridge knifeman, according to witnesses.
In the fallout, witnesses have described the actions of onlookers who helped fight off the individual, identified by police as 28-year-old Usman Khan.
One person, in particular, has stood out on social media.
"A guy who was with us at Fishmongers Hall took a 5' narwhale [sic] tusk from the wall and went out to confront the attacker," tweeted Amy Coop, who was on the scene.
"You can see him standing over the man [with what looks like a white pole] in the video. We were trying to help victims inside but that man's a hero."
The attack started at Fishmongers Hall, a heritage-listed building that was hosting a University of Cambridge-organised event on rehabilitating offenders.
Footage from the attack shows a man holding a long, white item which matches with Ms Coop's description.
Others shared images of an individual with a fire extinguisher helping the man with the tusk.
One user posted an image of the tusk before it was removed from the historic venue.
A narwhal, dubbed the "unicorn of the sea" by the World Wildlife Fund, is a whale with long tusks protruding from its head.
The man who took the tusk is yet to be identified, but praise is already mounting for the quiet hero.
"I ... want to pay tribute to the extraordinary bravery of those members of the public who physically intervened to protect the lives of others," Prime Minister Boris Johnson said.
"For me, they represent the very best of our country and I thank them on behalf of all of our country."
The knifeman, who was wearing a suspected hoax-explosive device, was shot dead by police after the daylight assault.
"This individual was known to authorities, having been convicted in 2012 for terrorism offences. He was released from prison in December 2018 on licence," Neil Basu, head of UK counter-terrorism policing, said in a statement.
"We believe that the attack began inside before he left the building and proceeded onto London Bridge, where he was detained and subsequently confronted and shot by armed officers," he said.
Metropolitan Police chief Cressida Dick said she was "deeply saddened and angered that our city has again been targeted by terrorism".
The stabbings took place on so-called "Black Friday" - one of the year's busiest shopping days in the run-up to Christmas.
Additional reporting: AFP