Five people are reportedly being held by police after a raid at flats in Barking.
Footage broadcast by Sky News showed an ambulance outside the Kings Road flats.
Tara Milan told The Daily Telegraph four men were detained in the flats but one man tried to escape armed police.
She said: “I saw them bringing them out of the flat opposite, around 7am.
“One man tried to flee and they shot him outside my house. They put him in an ambulance and then the others in a police van.”