South Africa must investigate Zimbabwean officials over allegations they tortured opposition figures in 2007, a Pretoria high court has ruled.
Under international law, South Africa has a duty to investigate crimes against humanity, the judge said.
Prosecutors had previously refused to investigate the officials, who had travelled to South Africa.
South Africa was the first African country to recognise the International Criminal Court.
The case was brought by the Southern Africa Litigation Centre (SALC), along with the Zimbabwean Exiles Forum (ZEF), many of whose members fled to South Africa saying they had been tortured by Zimbabwean security agents.
It centres on an incident in 2007, when supporters of then-opposition Movement for Democratic Change say they were tortured after a raid on their party headquarters.