POLICE on Sunday (6) declared a "major incident" after several people were stabbed in the centre of the country's second city, Birmingham.
Officers said they were searching for a man in relation to a two-hour stabbing spree that left one man dead and seven people injured, two of them critically.
Violence broke out at about 12:30am in and around the Arcadian Centre, a popular venue filled with restaurants, nightclubs and bars.
West Midlands Police confirmed "a number" of stabbings at four locations, but said it had no information on reports that shots had been fired.
"We are treating all four of those incidents as a linked series," West Midlands Police Chief Superintendent Steve Graham said.
"We are searching for one suspect and inquiries to identify and then trace that suspect are ongoing."
He said there was no suggestion that the attacks were targeted at any section of the community or were gang related.
"At this stage we can't find a particular motive, but it does appear to be random in terms of the selection of people who were attacked," he said.
Foreign Secretary Dominic Raab said he had no information to indicate the incidents were terrorism related but the public should stay "very vigilant".
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.
'Groups upon groups'
Cara Curran, a nightclub promoter, was working at the Arcadian Centre on Saturday night.
She told AFP 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 said.
"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."
Curran said the violence caused people in the area to flee the scene.
Police and other emergency services arrived quickly and cordoned off the area.
The elected mayor of the West Midlands Andy Street said there had been a "series of incidents" in the Hurst Street area, which is in the heart of the city's Gay Village district.
"They look to be related but the motivation for them is not yet understood. The area is calm and the advice to the public is to go about their business as normal," he told BBC television
Television footage showed forensic specialists in protective clothing poring over the scene, which was taped off and guarded by officers.
"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 said.
"At this early stage it would not be appropriate to speculate on the causes of the incident."
Bob Blackman MP speaks during the event