Tihar jail sources said some other prisoners of Jail numbers 1, 2 and 4 also joined the fight.
Two inmates were killed and over a dozen undertrials and Tihar jail staff suffered critical injuries in a gang war inside the high-security prison on Wednesday, police said.
The incident took place around 2 pm in jail No. 1 when three prisoners of the high security ward -- Ishwar, Vijay and Shadab -- were being taken back to their ward after a routine medical check-up in the jail dispensary.
When they were being taken back to their ward with police escort and prison officials, three other prisoners of another gang -- Anil, Vasu and Sandeep -- attacked them with hand-made weapons called "Kattan", Additional Inspector General (Prisons) Mukesh Prasad told IANS.
Ishwar and Anil, both in their late 20s, were killed in the attack.
Tihar jail sources said some other prisoners of Jail numbers 1, 2 and 4 also joined the fight, leading to injury to about a dozen undertrials and security staff.
Mr Prasad said jail staff and some other prisoners were also injured while trying to control the situation.
The injured were taken to the Deen Dayal Upadhyay Hospital where their condition is said to be stable.