Three men have been taken to hospital after a stabbing on a beach.
Merseyside Police said the victims were taken to hospital by air ambulance after emergency services were called to Formby beach in Sefton at about 7.10pm on Sunday.
Detective Superintendent Mark Baker said: “At this early stage we believe that these incidents are linked, but are keeping an open mind as to the motives behind them.
“However, we know the community of Formby and beyond will be alarmed to hear about what has happened and will share our determination to find those responsible and remove them from the streets.
“Officers remain at the scene and are available to support any residents looking for information or support.
“I know that there were a number of people on the beach this evening, and I’d like to urge anyone who saw what happened to come forward and help us to identify the offender as soon as possible.
“It is appalling and sad that on a sunny day like today when people have been out enjoying themselves, we are patrolling our beaches after such a horrific incident.
“Knife crime has no place whatsoever in our communities and we’re doing everything we can to bring the offender to justice.”
Formby beach is a National Trust site and one of the few areas in the UK with a red squirrel population.
The force said CCTV and forensic inquiries were ongoing.
Anyone with information can contact police via the social media desk @MerPolCC on Twitter, through Merseyside Police Contact Centre on Facebook with reference 978 of 30/05 or call Crimestoppers anonymously on 0800 555 111.