A missing 16-year-old from Wales could be in Woolwich, Abbey Wood, Thamesmead or Lewisham, police say.
Aisosa Henkoma, from Capel Curig, was last seen in Woolwich town centre on June 16 at around 4.20pm.
He is known to have friends and associates in the Woolwich, Abbey Wood and Thamesmead areas.
Aisosa also frequents Lewisham and Croydon and has been known to travel to Margate.
Police are concerned for his welfare and believe that he is still in south east London.
Anyone with information should call Detective Constable Rosemarie Caldwell on 020 8284 9403 or police on 101.