The death toll in a London tram derailment has risen to seven and police have arrested the driver.
People were trapped inside and more than 50 were taken to hospital after the derailment in Croydon, in the south of the British capital, on Wednesday morning.
Mayor of London Sadiq Khan said the number of dead "may well increase".
The Rail Accident Investigation Branch (RAIB) said the tram was travelling at a "significantly higher speed than is permitted".
The tram driver, 42, from Beckenham, has been arrested on suspicion of manslaughter.
British Transport Police said they were investigating whether he fell asleep.
The Rail Accident Investigation Branch said the derailment happened on a sharp curve with a 12 mph speed limit. Photo: AFP
London Ambulance Service said 51 people had been taken to two hospitals.
St George's Hospital in Tooting was treating 20 people, four of whom were seriously injured and 16 who were walking wounded. Clinical director Dr Phil Moss said three were having surgery and could be kept in for "several days or even weeks."
Croydon University Hospital's medical director Dr Nnenna Osuji said 31 patients were brought in by ambulance while seven others arrived on foot.
The tram toppled on its side next to an underpass and appears to have derailed where the track branches.
The RAIB said it was it was negotiating a "sharp, left-hand curve" which has a speed limit of 12 mph.
Trams are not fitted with any safety protection systems that apply the brakes automatically if they are going too fast, according to the Office of Rail and Road.
Andy Smith said he was waiting at a nearby bus stop when he heard "what sounded like a screeching noise, then a bang".
He said: "[I looked] down the track and I saw carnage. There was a lot of screaming, panicking and commotion. It was a macabre scene."
Peter Allan Jones, who lives in a flat opposite to where the tram derailed, said he saw the "walking injured" moving down the tracks towards the main road.
He said one man was "shouting" and had to be restrained by police but "everyone else seemed quite sombre and quite shocked".
Mayor of London Sadiq Khan said the number of dead "may well increase". Photo: AFP
Resident Pat Rooke said: "They do come around that corner very fast sometimes, and it is quite a sharp bend."
British Prime Minister Theresa May offered her thoughts and prayers and said the government was "closely in touch with the emergency services and other authorities to ensure that all is being done that is necessary to deal with this terrible incident."
Mr Khan said: "I am in close contact with the emergency services and Transport for London, who are working extremely hard under very difficult circumstances to get the situation under control and treat those who have been injured.
New Zealand's Ministry of Foreign Affairs and Trade said there were no indications any New Zealanders were involved in the crash.
- BBC
