Police were called at around 0410hrs on Sunday, 31 October, to a stabbing in East Street, Barking.
Officers attended along with London Ambulance Service.
Three men, all aged in their late 20s, were taken to hospital for treatment.
Two of the men are in a critical condition, one having sustained stab injuries and the other with head injuries. The third man sustained an injury to his hand.
Detectives from East Area CID are investigating. These has been no arrest at this early stage.
Anyone with information or any witnesses are asked to call police on 101, ref 1982/31oct.
To remain anonymous, please contact Crimestoppers.