The teenager was hit in the stomach and leg at around 11pm while standing outside The Lounge Bar in Crosby, Liverpool. It unfolded in front of horrified crowds, but thankfully no one else was injured in the “targeted” attack.
He was rushed to hospital for treatment a short time later and, according to Merseyside Police, is currently fighting for his life.
Chief Inspector Steve Hardy urged anyone with information to contact them.
In a statement, the force said: "Detectives are appealing for information following a shooting left a male injured in Waterloo last night, Friday 2 July.
"At around 11.15pm, it was reported a 17-year-old male had been shot outside The Lounge Bar on South Road, near its junction with Mount Pleasant.
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"The victim has been taken to hospital for treatment to injuries to his torso and legs consistent with being shot with a firearm, and his condition is described as critical.
"Forensic, witness and CCTV enquiries are underway."
Chief Insp Hardy said: “Our investigation is in its very early stages, and we are keen to hear from anyone who saw or heard this incident.
“This area of South Road has a number of bars and restaurants so we know it would have been busy on a Friday night, and we have spoken to a number of witnesses already.
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“I want to appeal to anyone else who was in the area and may have information, or who was in a passing vehicle and might have dashcam, to contact us.
“Any details or footage could prove key to our enquiries as we piece together what happened.”
He added: “We understand the fear that gun crime causes to residents and visitors to the area – many of those on South Road last night would have simply wanted to enjoy a peaceful night out with friends and family.
“I want to assure people in the community that we think this was a targeted attack, and that our investigation will leave no stone unturned as we seek to put those responsible before the courts and take the firearm used off our streets.
“We continue to regularly seize weapons and arrest suspects connected to such incidents and will act on all information provided on gun crime to remove weapons and those who use them from the community.
"Please come forward with what you know, directly or anonymously, and we will do the rest.”
Anyone with information on this incident is asked to contact Merseyside Police social media desk via Twitter @MerPolCC or Facebook Merseyside Police CC with reference 21000462538. Always call 999 if a crime is in progress.
You can also call 101 or contact the independent charity Crimestoppers anonymously, on 0800 555 111 or via their online form at: https://crimestoppers-uk.org/give-information/give-information.