Police and emergency services responded to an incident in Bohemia Road, Hastings at around 8pm last night (May 15).
A local woman aged 50 suffered injuries consistent with a stabbing and has been taken to hospital.
The incident happened at about 7.50pm on Monday, May 15.
Residents on Facebook reported seeing a police search helicopter and an air ambulance, following the incident.
There will be an increased police presence in the area while it is responded to.
Police are searching for a man seen wearing a black puffa-style jacket who went in the direction of Falaise Road.
Witnesses or anyone with information can report it to Sussex Police on 999 and quote Op Florida.