Three teenagers have been found suffering stab injuries in nearby streets in north-east London.
Scotland Yard said officers were called after the victims, one aged 15 and two aged 19, were discovered in the Chingford area of Waltham Forest this afternoon.
Police were first called to Lukin Crescent, a short distance from Chingford station, at 3.07pm on Monday.
There they found a 15-year-old boy with a stab injury.
Shortly afterwards, officers were called to Westminster Gardens where two 19-year-old men were also found with stab wounds.
All three victims were rushed to hospital, a Met Police spokesman said.
Photos taken in Westminster Gardens show a police car and cordon outside a house, while other images posted on social media show an air ambulance landing nearby.
Police later said none of the victims had suffered life-threatening injuries. Four arrests have been made.
Prime Minister Theresa May recently held a summit on knife crime following a spate of bloodshed across London and the rest of England since the start of 2019.
Last week a man appeared in court in connection with five knife attacks that took place in Edmonton, north London.
One of the victims, a 45-year-old woman, was left paralysed after her spinal cord was severed in the attack.
Earlier this year 14-year-old Jaden Moodie was stabbed to death in Leyton, in Waltham Forest, after a group of five men in a black Mercedes rammed him off a moped, police believe.
Anyone with information is asked to call police on 101 or Crimestoppers anonymously on 0800 555 111.
