A second man has been arrested in connection with three unprovoked assaults on women in a three-week period.
A 17-year-old youth from Hilsea, Portsmouth, Hampshire, has been arrested on suspicion of grievous bodily harm with intent.
A 30-year-old man from Waterlooville who was arrested on Friday remains in police custody, which has been extended to 10.20pm tonight.
The first assault took place at 10.40pm on June 20 when a 20-year-old woman who was walking along Southampton Road, Portsmouth, was approached from behind and assaulted.
She received a chest injury, which was serious but not life-threatening.
In the second incident, a 45-year-old woman was approached by a man along the shoreline of Ports Creek in Hilsea and was stabbed in her chest.
The man ran off towards Hilsea Lines.
Police were called to a third incident shortly after 1pm on Friday following a report of an assault by a man on a woman who was walking in an alleyway between Colwell Road and Northern Road in Cosham.
The woman was treated in hospital for her injury and was released later the same day.
A Hampshire police spokesman said: "Women and the wider community are advised to continue to be vigilant. Advice is to continue with your daily lives and businesses as you would normally. However, where possible take extra precautions and report any suspicious behaviour on 101.
"Increased police patrols remain in place in the area to continue to provide reassurance to the community."