Newington Causeway and part of Southwark Bridge Road were sealed off on Monday morning after a man was shot dead outside the Ministry of Sound club in Gaunt Street near Elephant & Castle.
Police say that the dead man, thought to be in his twenties, was shot in Gaunt Street at about 4.40am on Bank Holiday Monday.
Another man, aged 29, also suffered gunshot wounds. He is in a stable condition in hospital.
The incident led to the closure of Gaunt Street, Newington Causeway and the southern end of Southwark Bridge Road. Buses were diverted via Borough Road.
A number of shootings have taken place near the nightclub in recent years.
The club, owned by James Palumbo, celebrates its 18th anniversary next month.
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