(Adds Massmart comment)
JOHANNESBURG, Sept 29 (Reuters) - A violent protest flared on Friday at a Johannesburg store run by Wal-Mart's South African unit Massmart where workers have staged a week-long strike over wages.
Marune Rossouw, a Thomson Reuters employee, said she was trapped inside the store with other shoppers as protesting staff rampaged through the car park, throwing stones at cars.
Massmart confirmed that a group of picketing members from the South African Commercial Catering and Allied Workers Union threw objects at the window of one of its Makro liquor stores at around 0800 GMT.
"As a result of the security protocols, approximately 35 customers and staff were confined within the store whilst arrangements were made to ensure that they could exit the site safely," a Massmart spokeswoman said.
There was no immediate comment from union officials. The store, in a middle-class northern suburb of Johannesburg, has since resumed trading.
Massmart shares were down 1 percent at 110.12 rand by 0955 GMT, compared with a 0.8 percent rise in the JSE's All-share index. (Reporting by TJ Strydom and Ed Cropley; Writing by Ed Stoddard; Editing by Keith Weir)