A 16-year-old boy sustained life-threatening injuries in the incident in Liverpool Road, Worthing, at about 5.30pm on February 13.
He remains in hospital in a serious condition.
Officers initially made two arrests in connection with the incident, and continue to carry out increased high-visibility patrols in the town centre to provide reassurance to the public.
Now, a further three teenage boys have been arrested in connection with the investigation.
On Tuesday, February 14 police arrested a 15-year-old boy on suspicion of causing grievous bodily harm.
On the same day, they also arrested a 16-year-old boy on suspicion of conspiracy to cause grievous bodily harm.
Both boys remain in police custody at this time.
On Wednesday, February 15, officers arrested a 13-year-old boy on suspicion of possession of an offensive weapon in a public place and affray. He also remains in custody at this time.
A further order under Section 60 of the Criminal Justice and Public Order Act 1994 has been made for the next 24 hours.
The order gives police officers extra powers to search anyone and seize any weapons found in Worthing town centre, without grounds, to prevent further incidents taking place.
Those who fail to submit to a search will be committing a criminal offence.
West Sussex local policing Superintendent Nicholas Dias said: “We are continuing to make progress with our investigation into this incident, with five boys arrested and three currently in custody.
“This was a distressing incident, and I encourage witnesses or anyone with information about what happened to come forward and report it to us.
“A decision has been made to issue a further Section 60 order, which reflects the seriousness of the incident and the investigation.
“It is a decision which has not been taken lightly, and is a short-term measure aimed at targeting and disrupting these incidents.
“The order will remain in place for the next 24 hours.
“Meanwhile we continue to respond to peoples’ concerns about anti-social behaviour from a small group of young people in and around the Worthing area.
“We are working closely with our partners, including Worthing District Council and key partners in Children’s Services to address these issues and keep our communities safe.”
Sussex Police can also confirm that a 13-year-old boy arrested on February 13 on suspicion of conspiracy to cause grievous bodily harm has been bailed, pending further enquiries.
A 17-year-old boy who was arrested on suspicion of the same offence on February 13 has been released without charge.
Witnesses or anyone with information about this incident are asked to report it to Sussex Police online and quote Operation Central.
