International Relations Minister Maite Nkoana-Mashabane has broken her silence on assault allegations against Zimbabwe's first lady Grace Mugabe. The minister granted Mugabe diplomatic immunity last weekend, despite South African model Gabriella Engels laying assault charges against her. Mugabe was accused of beating Engels at a Sandton hotel where her two sons were staying. Pictures of Engels with deep cuts to her forehead surfaced on social media, sparking public outrage. Mugabe returned home on Sunday morning after being granted diplomatic immunity. Minister Nkoana Mashabane says the incident was regrettable.