LONDON — A man was killed and seven people injured in late-night stabbings in a busy nightlife area of the central England city of Birmingham, police said Sunday.

Police said they were searching for a lone suspect in what appeared to be random attacks.

Chief Superintendent Steve Graham of West Midlands Police said detectives were still investigating the motive but "there is absolutely no suggestion at all that this is terror-related."

West Midlands Police said officers were called to reports of a stabbing shortly after midnight on Sunday. That was soon followed by reports of other stabbings across the city center over a period of about two hours.

Police said they believed the stabbings were linked and had launched a murder investigation.

Graham said two of the seven injured people, a man and a woman, were in critical condition in hospitals. Five others received "relatively minor" injuries.

The site of one attack is in the city's Gay Village, but Graham said there was no suggestion the crime was "motivated by hate."

Police cordoned off an area in the center of the city full of bars and nightclubs. Witnesses said they were busy on Saturday night, with many people eating and drinking at outdoor tables. More cordons and blue forensic tents were set up about half a mile away, near the city's Snow Hill train station.

Cara Curran, a club promoter, said she saw multiple people fighting in the street.

"It was one group of boys against another group of boys," she told the BBC, adding that "racial slurs" were being thrown.

Foreign Secretary Dominic Raab said it was "a very serious incident. Our thoughts and prayers are with the victims and their families."

West Midlands Mayor Andy Street urged people "to not speculate about the incident" and to "remain calm but vigilant." 

Official statistics show knife crime is on the rise in the U.K., where most guns are outlawed, though the number of homicides with blades fell in 2019 from the year before.

Britain has seen several recent knife attacks, including a stabbing rampage in a city park in Reading, near London, in June that killed three people. A Libyan man has been charged.