Two people have been confirmed dead after a helicopter crashed into a road in central London, hitting a crane on top of a tower block and exploding into flames, just streets away from MI6 and Vauxhall station and the site for the new US embassy.
The pilot and someone on the ground were those killed in the crash, according to emergency services.
Dense black smoke was billowing from the area, close to the River Thames after the helicopter spiralled to the ground in what eyewitnesses described as "a massive ball of flame."
The Huffington Post UK's Jessica Elgot has spoken to a policeman who said his radio line was 'filling up with casualties.'
Four people are in hospital, according to the London Fire Brigade, who rescued a man from a burning car at the scene.
Nine people suffered injuries and one person is critically ill, the Met police stated.
The two people who died are the pilot and somebody on the ground, the Met police told a press conference.
Flaming wreckage and aviation fuel covered the road as witnesses reported seeing cars on fire and hearing people screaming.
The helicopter is believed to have crashed near Wandsworth and South Lambeth Road after colliding with a crane shrouded by fog on top of St George's Tower, a residential building currently under construction.
London Fire Brigade confirmed that the crane at the St George's Wharf development appeared to have been left "in a precarious position".
Bruce Grain of London Fire Brigade told Sky News that two cars were hit by the helicopter as it landed on the road.
Two person are reported on board the helicopter at the time of the crash, but an "unknown" number of people are involved in the collision.
Scotland Yard said: "Two people have been confirmed dead at the scene. We have no further details. Two have been taken to south London hospital. We await a condition update.
"We will confirm further details on the incident as soon as possible."
At least seven ambulances are at the scene of the crash. According to Reuters, Scotland Yard has said there is no link to terrorism
One resident near the St George's wharf tower told Sky News the noise at the time sounded like a "gas explosion" and felt like a mini-earthquake.
Sarah-Beth Casey said: "It was like a gas explosion. I looked up to see debris falling off the tower."
Eyewitness Chris Matthison told BBC News: "There was some damage to the crane. It's possible the crane is lying across Nine Elms road.
"The top of the nearest building is steeped in mist and difficult to see."
He added: "I heard a very unusual dull thud, then there was silence. The silence really took my imagination. Emergency services responded very quickly."
Commuters on the busy route into central London have reported hearing loud bangs around 8am from as far away as Oxford Circus at the time the crash occurred.
Vauxhall station was initially closed and traffic is gridlocking the surrounding areas.
The Met Police have said that the helicopter is not one of their fleets and ITV have reported that the craft is an Agusta 109 based in Yeovil.
London Fire Brigade said 22 different fire and rescue resources are involved as part of a "large response."
A spokesman for Berkeley Group, which owns St George, the development company for the building, said in a statement:
"We can confirm a helicopter collided with a crane at St George Wharf at 8am this morning.
"Our thoughts at this time are with the friends and families of those killed in this tragic incident.
"Emergency services are on the scene and authorities are investigating the circumstances.
"We are offering our full support and assistance to the emergency services."