A South African court has ordered prosecutors to investigate Zimbabwean officials accused of torturing opposition figures in 2007.
The judge said South Africa has a duty under international law to investigate crimes against humanity.
Prosecutors and the police previously refused to investigate Zimbabwean officials travelling to South Africa, citing ‘political considerations’.
South African Judge Hans Fabricius ruled that the police force and the National Prosecuting Authority had acted "unconstitutionally and unlawfully" - and ordered them to conduct an investigation.
"In my view it is clear when an investigation under the ICC Act is requested, and a reasonable basis exists for doing an investigation, political considerations or diplomatic initiatives are not relevant," Judge Hans Fabricius said.
Human rights groups have welcomed the judgment.
"This judgment will send a shiver down the spines of Zimbabwean officials who believed that they would never be held to account for their crimes but now face investigation by the South African authorities," said human rights lawyer Nicole Fritz of SALC.
However, Zimbabwean Justice Minister Patrick Chinamasa dismissed the ruling.
"We have done nothing wrong in this country that would justify bringing us under the jurisdiction of the ICC, even if we were a state party," he said.
"The ICC is there for serious crimes against humanity - not ordinary crime, which is what these exiles are trying to suggest." Chinamasa told the BBC.
