Armed police officers, some in full riot gear, were stationed outside St Anthony's Catholic Church and the cemeteries where the burials took place. Cars and some of the mourners were searched.
The funeral services of Johnny Jacobs, 43, and Gavin Adams, 49, were held within two hours of each other at the same church.
Adams, the leader of the Dogan gang, was shot in Meadowdale on March 7 . The next day, in an alleged revenge killing, Jacobs, from the Sour Boys gang, was gunned down .
Jacobs's grief-stricken wife, Belinda, broke down in tears yesterday as his coffin was lowered into the ground at the cemetery in Dawn Park, Boksburg.
Minutes earlier his childhood friend, Marilyn Taylor, had said: "I grew up with Johnny ... he was very respectable. It's really sad."
Two hours afterwards, the church was packed again for the funeral of Adams.
Pastor Nathan Isaac urged mourners and the community to "stop the violence".
He said: "Violence destroys us all ... we are more than violence. We cannot allow this spiral of violence to continue. We need to show that we are more than that."
Adams was buried at the Boksburg Cemetery. His family arrived in a white stretch limousine. His daughter, Logan, wrote a letter to her father which was read out at the grave side.
She said: "The pain is so intense it takes my breath away. Never again will I laugh with you ... tears will fall but we will always remember the happiness you brought in our lives."
Adams's coffin was lowered into the ground while the Boys 2 Men and Mariah Carey song One Sweet Day played in the background.
The continuing gang war has also been blamed for the death of a third man, Anton Williams, 32, although his family have denied he was a member of the gangs.
William Orr, 51, has been arrested in connection with the murder of Jacobs. He appeared in the Boksburg Magistrate's Court on Thursday and the case was adjourned to March 27 for a bail application.
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