Officers were called to Newham in East London on Monday afternoon,
Officers attended and found two teenage boys - aged 14 (victim 1) and 17 (victim 2) - with gunshot injuries.
London Ambulance Service attended the scene.
They were taken to an east London hospital.
Victim 1 - His injuries are being treated as life threatening.
Victim 2 - His injuries are not life threatening but are believed to be life changing.
No arrests at this time. Enquires continue.
Chief Superintendent Ade Adelekan, in charge of policing Newham said: "Sadly today two young men have been shot on our streets, one of whom remains critically ill in hospital.
“We are only too well aware that this incident comes after a number of shootings and firearms discharges that are blighting our communities and seriously injuring our young men.
“Tonight there will be extra officers on duty throughout our borough, and due to my serious concerns that others may retaliate in response to today’s incident I will be authorising my officers to use stop and search throughout the borough under Section 60.
“Proactive work will continue with our borough teams and specialist units such as Trident Area and Crime Command to investigate and catch the people responsible for these offences. Violence has no place on our streets, and we have already made four arrests in connection with recent firearms offences.
“I want the community of Newham to help us tackle this - if you have any information about people carrying or supplying firearms please let us know and we will take action.”
Enter a name and e-mail address and we will e-mail this website link too them.