Updated

South Africa's main opposition party says a parliamentary committee has agreed to summon the foreign minister to explain the decision to grant diplomatic immunity to Zimbabwe's first lady, who is accused of assaulting a young model at a Johannesburg hotel.

The Democratic Alliance said Wednesday that parliament's international relations panel will ask the minister, Maite Nkoana-Mashabane, to explain why Grace Mugabe was allowed to return to Zimbabwe on Sunday despite calls for her prosecution.

The Democratic Alliance says in a statement that a date for Nkoana-Mashabane's appearance before the committee should be scheduled urgently and that "South Africa cannot be treated as a playground for international criminals."

The 20-year-old Gabriella Engels claims that Mugabe attacked her on Aug. 13, whipping her with an extension cord that cut her forehead.