Four men in their 20s were found with stab wounds following calls to police about a fight in north London on Sunday evening.
One of the men remains in hospital in a serious but stable condition, police said.
The fight on Fraser Road, Edmonton, followed a shooting in Edmonton on Saturday in which two men and a teenage boy were wounded.
Police believe the two incidents are linked. One person has been arrested.
A Scotland Yard spokesman said: "At this early stage, officers believe the incident is linked to the shooting in Gordon Road, Enfield on Saturday, 17 November."
The force added that both attacks "appear to have been targeted against specific individuals".
During Saturday's shooting, a shotgun was fired twice into a minicab in which the men were sitting on Gordon Road.
One passenger's injuries were described as "potentially life-changing".
Police have appealed for witnesses or anyone with information to come forward.