The incident happened in High Street, East Ham just after 1pm today (January 29).
Paramedics arrived in less than four minutes and a patient was found injured with “several wounds”.
He has been taken to hospital as a priority where his condition is unknown.
Cordons are in place shutting access both ways from Central Park Road to Barking Road.
A London Ambulance Service spokesperson said: “We were called at 1.02pm today (29 January) to reports of a stabbing in High Street South, East Ham.
“We sent an ambulance crew, a paramedic in a fast response car and an incident response officer. We also dispatched London’s Air Ambulance.
“The first paramedic arrived in less than four minutes.
“We treated a patient for several wounds and took him by road to a major trauma centre as a priority.”
The Metropolitan Police has been approached for comment.
