People will be checked for knives when entering "certain premises" in Cardiff city centre after violent clashes, South Wales Police have said.
The force said "screening devices" would be in place to stop people carrying weapons.
On Saturday, six people were taken to hospital after a clash between two groups in Queen Street.
And on Wednesday, a 17-year-old was stabbed in the Canton area of the city.
Three teenagers and a man have since been arrested.
The force has said both incidents were "not random" and involved groups of local teenage boys "targeting each other".
Det Sup Esyr Jones said: "There will be a very visible police presence across the city this weekend and screening devices will be present outside some city centre premises to help maintain a safe environment, reassure the public and deter anyone thinking of carrying a weapon."
A 17-year-old boy was taken to the University Hospital of Wales with non life-threatening injuries after being stabbed in Broad Street, Canton, at about 10:00 GMT on Wednesday.
On Thursday a 16-year-old boy, from Canton, was arrested on suspicion of assault, while a man, 43, from Penarth, was arrested on suspicion of assisting an offender.
It brings the total number of people arrested for the Canton incident to four.
Earlier this week a 15-year-old boy, from Riverside, was arrested on suspicion of violent disorder and possession of an offensive weapon. He has been released on police bail.
While a boy, 17, from the Grangetown area, was arrested on suspicion of violent disorder and assault on Thursday, and remains in custody.
It was the second violent incident to take place in the city in a matter of days.
On Saturday, six people were taken to hospital with injuries including stab wounds, after a violent clash between two groups in Queen Street.
Detectives have said the incident involved two groups, from the Grangetown and Rumney areas of the city.
Seven boys aged 16 and 17 have been arrested on suspicion of violent disorder and have been released on bail pending further inquiries.
"I want to re-emphasise that Wednesday's stabbing and Saturday's violent disorder in the city centre are not random attacks, they involve groups of local teenage boys targeting each other and we appeal to the community for information," Det Sup Jones said.
On Thursday police held a virtual meeting with community leaders in the Canton, Riverside and Grangetown areas of the city in a bid to deter knife crime.
Officers had been temporarily granted increased stop and search powers under Section 60 of the Criminal Justice and Public Order Act, allowing them to search anyone in the areas of the city.Four people were stop searched as a result of a Section 60 notice in the Canton and Grangetown areas on Wednesday and Thursday.