BBC News reports that approximately 40 fire engines and 200 firefighters arrived at the Grenfell Tower on the Lancaster West Estate to combat the enormous fire, which eyewitnesses say has trapped the building's occupants.
One witness tweeted: "People r screaming for help & I saw a lady jump out! God be with innocent souls stuck there. View from my window."
The horrifying footage appears to show the 120-unit building crumbling, with flames shooting from all angles.
Another Twitter user tweeted: "Fire consuming Grenfell Tower. People screaming for their lives. Horrible."
Yet another witness wrote: "People are flashing SOS symbols from their windows. I'm crying so much."
According to NBC News, the London Metropolitan Police stated that while no casualties have yet been confirmed, two people received medical attention for smoke inhalation and a number of others are being treated for injuries.
Business Insider Senior Editor Josh Barro reposted a link to a collection of blog posts claiming that Grenfell Tower had been "a flagrant fire hazard."
"A years-long series of blog posts contending the apartment tower engulfed in flames in London tonight was a flagrant fire hazard," Barro tweeted.
It's important to note authorities do not yet know what caused the massive fire.
This story is developing. Check back for updates.