Sussex Police said that they were called to a property in Manning Road, Littlehampton, West Sussex, where two occupants of an address had been attacked.
There were four suspects who police described as wearing dark clothing and balaclavas, and made off from the house before police arrived.
The victims, aged 22 and 25, were taken to hospital where they received stitches for head wounds, believed to be as a result of a knife being used, police said.
A meat cleaver had been reported to police as being one of the weapons used. One neighbour saw the victims 'absolutely covered in blood'; click here to read more reactions from people living nearby.The incident sparked a large-scale police response, with at least 14 different police units called to the scene, including PCSOs going door-to-door.
Scene of crime officers were also at the address, and photographs have showed evidence being collected from the property.
Last night, a police spokesman said: “There is no evidence whatsoever that any members of the public are at risk.”
This morning, the suspects still had not been located.
A police spokesman asked for witnesses to come forward. They said: "Police are appealing for any witnesses to the incident or who may have seen the suspects running away to contact our 101 number, quoting CAD reference 886 of 24/01 or reporting it online."