It brought the number to four arrested in connection with the killing of the 26-year-old victim, who has not been named.

She was set upon in Liverpool on Friday night after getting into an argument with the occupants of a car, Merseyside Police said.

It is believed the woman was targeted and that she was known to her assailants. The attackers drove off after the incident.

Officers arrested a further two women, aged 19 and 25, on suspicion of murder. They had earlier executed warrants at three addresses in the Anfield area of Liverpool, arresting women aged 25 and 48 on suspicion of murder.

All four are being questioned by police and were expected to be kept in custody overnight. The attack took place at around 8.30pm on Friday on Woodville Terrace, Anfield.

Merseyside Police said they believe they know who the victim is, but had not named her ahead of informing all of her next of kin.

Detective Chief Inspector Richie Davies of Merseyside Police described the stabbing as "vicious and brutal".

Officers are particularly keen to speak to anyone who saw a small, dark car in the area at the time of the incident.

Witnesses can call Merseyside Police on 0151 777 4065 or Crimestoppers anonymously on 0800 555 111.