A window was smashed during an altercation between two customers in a shop at the Elephant & Castle.
The incident, just after 10am on Saturday, was at Davish News next to The Coronet in New Kent Road.
Passers-by rang the emergency services when one of those involved appeared to have been injured.
It was later confirmed that one person had sustained a stomach wound from the glass.
The shop remained open during the rest of day whilst a shutter was closed to protect a boarded up window.
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