Britain has been on high alert after two mass stabbings in London last year, which saw both perpetrators shot dead by armed officers.
British police has declared a "major incident" after several people were stabbed in the centre of the country's second city, Birmingham.
Violence broke out at about 2330 GMT on Saturday in and around the Arcadian Centre, a popular venue filled with restaurants, nightclubs and bars.
Police in Birmingham in central England said they were seeking a single suspect in relation to a series of stabbings in the early hours of Sunday that resulted in the death of one man and left another seven injured, two of them seriously.
Chief Superintendent Steve Graham said a murder inquiry had been launched but there was "no suggestion at all that this was terror-related.
"It does appear to be a random attack," he added.
West Midlands Police confirmed "a number" of stabbings but said it had no information on reports that shots had been fired.
The incident comes after several previous mass casualty stabbings, including one in the Scottish city of Glasgow on June 26, in which six people were injured, including a police officer.
A man was charged with murder after three people were killed in a park in Reading, west of London, the previous week in an attack investigated by counter-terrorism police.
Britain has been on high alert after two mass stabbings in London in the last year, which saw both perpetrators – convicted extremists released early from prison – shot dead by armed officers.
Knife crime in England and Wales increased six percent in the year to the end of March, according to the Office for National Statistics.
Birmingham, one of Britain's most ethnically diverse cities with a population of more than one million, has had an explosive recent history of gang violence.
In January 2003, one gang opened fire with an illegal semi-automatic sub-machine gun at a rival group. Two teenage girls who were bystanders were killed in the hail of bullets.
#UPDATE | We can confirm that at approximately 12:30am today we were called to reports of a stabbing in #Birmingham city centre.— West Midlands Police (@WMPolice) September 6, 2020
We immediately attended, along with colleagues from the ambulance service. A number of other stabbings were reported in the area shortly after.
'Groups upon groups'
Cara Curran, a nightclub promoter who was working at the Arcadian Centre on Saturday night said she saw "groups upon groups" of people fighting in and around the venue and heard the use of "racial slurs".
"I had seen a lot of tensions building through the night, which wasn't quite like what I've seen before," she told.
"I had left with my boyfriend. I heard a commotion and saw multiple police coming towards our direction. I headed towards where I saw them coming and it all just unfurled in front of me.
"It was quite a street fight. It didn't really look like fighting. It was just multiple people on top of each other, not one on one."
She added: "There was every ethnicity there, there was Asian, Black, White. It wasn't just this ethnicity against this ethnicity, it was a group of ethnicities with another group, and they sort of just went at it."
Passers-by fled the violence, as police and other emergency services arrived quickly and cordoned off the area. Forensic specialists were poring over the scene mid-morning.
As we wait for news on the major incident in Birmingham overnight, all our thoughts are with the victims and anyone else affected. Thank you to our emergency services.— Keir Starmer (@Keir_Starmer) September 6, 2020
Shabana Mahmood, who represents the area in the UK parliament for the main opposition Labour Party, described the events as "deeply concerning".
Local councillor Yvonne Mosquito, also of Labour, said the violence was "traumatic" for every one involved.
Mosquito, a former city lord mayor, praised police for tackling so-called "black on black" violence in Birmingham in the early 2000s.
But she said there remained a real issue with social exclusion among younger people, including "county lines" drug dealing.
The Arcadian centre, where Birmingham Gay Village and Chinese Quarter meet, was vibrant and popular although there had been "a bit of trouble" previously, she told.
"Work is still going on to establish what has happened, and could take some time before we are in a position to confirm anything," West Midlands Police added.
"At this early stage it would not be appropriate to speculate on the causes of the incident."