Police are investigating a multiple stabbing that took place on Formby Beach.
Emergency services were called to the National Trust-run location at around 7.10pm on Sunday following reports that three people had been stabbed.
A 16-year-old boy and two men, both aged 20, were airlifted to hospital.
One of the men is said to be in a critical but stable condition while the injuries suffered by the other and the teenager are not thought to be life-threatening.
CCTV and forensic enquiries are ongoing and Merseyside Police officers will be in the area this evening to speak to the community and gather information.
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.”
Anyone with information about the incidents is urged to contact Merseyside Police’s social media desk via @MerPolCC on Twitter or ‘Merseyside Police Contact Centre’ on Facebook with reference 978 of 30/05.
You can also contact the independent charity Crimestoppers anonymously on 0800 555 111 or via their online form.