Police claimed the victims died in a clash between two groups.
Two Sikh men, aged 29 and 39, were arrested on suspicion of murder after the horrific incident unfolded near Seven Kings train station in Ilford, east London, at around 7.30 p.m. on Sunday, Mail Online reported.
The three unidentified victims in their twenties and thirties were found with fatal knife wounds and pronounced dead at the scene.
Horrifying footage shared on social media showed a victim lying in a pool of blood at the foot of a staircase near the station. The gruesome clip shows a man not moving, with blood on the pavement and on the road.
Witnesses spoke of 'blood everywhere' and one victim 'bleeding from the neck'. The owner of a taxi firm opposite the station recalled a man with 'blood on his hands' coming into his building while pleading for help.
The Metropolitan Police were trying to identify the men and inform their families after launching a triple-murder investigation.
Former professional boxer Wadi Camacho shared a video clip after the incident, tweeting that one of the dead was 'bleeding from his neck'. In a follow-up tweet, he said: 'Trust me they are gone. The (man's) eyes fully open, not moving, and bleeding from his neck. Bloody everywhere.'
One person living near the crime scene said he saw an ambulance service working on one person, and then realised there were two other bodies, at which point he went outside to see what was going on. "I could see it all, one (body) to the left, two at the bottom of the stairs.
"It was like a bad day in Bosnia. It was pretty horrific really. I've never seen anything like it to be honest. It's like something on a movie."
( With inputs from IANS )