BIRMINGHAM, (United Kingdom): Detectives in Britain's second city of Birmingham on Sunday launched a hunt for a knifeman who killed one and critically injured two in a series of random stabbings over several hours.

Five others suffered minor injuries in the attacks, which happened at four separate locations in the busy city centre between 12:30 (2330 GMT Saturday) and 2:30 am.

One of the areas was in the heart of Birmingham's Gay Village but officers ruled out a hate crime. They also rejected any links to gang violence and terrorism.

"It does appear to be random in terms of the people that were attacked," said Chief Superintendent Steve Graham of West Midlands police. "This is being treated as a homicide."

Britain has been on high alert after two mass stabbings in London in the last year, which saw armed officers shoot dead both perpetrators -- convicted Islamic extremists who had been released early from prison.

In June, a man was charged with murder after three people were stabbed to death in a park in Reading, west of London, in an attack under investigation by counter-terrorism police.

Six people, including a police officer, were then injured at a hotel housing asylum seekers in the Scottish city of Glasgow. Armed police also shot dead the suspected attacker.

Stabbings in England and Wales increased six percent in the year to the end of March, according to the Office for National Statistics.

No details were immediately released about the identity of the victims other than that the person killed was male, and the two people critically injured are a man and a woman.