The victims – aged 15, 16 and 18 – were playing the popular mobile phone game in Whittington Park in Holloway on Tuesday night when three male teenagers approached them.
One of the alleged robbers, believed to be a 16-to-17-year-old referred to as “Kushi”, brandished a handgun while an accomplice demanded they hand over their devices.
The three victims handed over their smartphones and left the scene shocked but unscathed, police said.
The attack came just 30 minutes after another armed robbery at the entrance to Whittington Park at 10pm, in which a 24-year-old man had a silver handgun pressed to his waist as three men demanded he hand over his possessions. He too left unharmed after being told to turn around and walk away.
Scotland Yard said they believe the incidents are linked as thesuspect descriptions and methods used were identical and both happened close to each other.
Investigating officer PC Kevin Yeung said: “These were really shocking attacks on young people walking around a much-loved park.”
Appealing for witnesses, he said: “Were you in the area? Did you see anything?
“My team are keen to hear from anyone who can help lead us to the culprits. Robberies where a gun is shown or indicated are very rare and we are keen to apprehend those involved as soon as possible.”
Police also released descriptions of the three suspects involved. The first is described as an Asian male, believed to be 16 or 17, 5ft 6ins tall and referred to as “Kushi”. He was wearing a black zipped jumper, black trousers and a black bandana covering his face.
The second suspect is described as an Asian male, also believed to be 16 or 17 and 5ft 8ins tall. He was wearing a dark grey puffer jacket.
The third suspect is described as an Asian male, believed to be 16. He was wearing a black zipped jumper, black North Face gilet, and dark trousers.