The 19 alleged coup plotters from the Democratic Republic of Congo were today formally charged in a South African court.
The rebels are accused plotting to stage a coup in their home country.
South African police arrested the men in Limpopo province after several months of investigations.
Police first received a tip off on the presence of the group in the country last September and they managed to infiltrate it.
On Tuesday the police conducted a pre-dawn raid, where they arrested the 19 insurgents.
They are alleged to have transgressed the Foreign Military Assistance Act.
The group is accused of preparing to receive military training to topple President Joseph Kabila and was subject to a special police sting operation.
"They intended on unseating President Kabila unconstitutionally," government prosecutor Shaun Abrahams told the Pretoria Regional Court.
Abrahams told the court that the men were members of the Union of Nationalists for the Renewal (UNR) of the DRC.
The men were not asked to plead and were remanded in custody till February 14.
The case was also postponed to allow investigators to verify their identities and for the suspects to engage lawyers.
Police sources said they had "received credible information about a coup and that there were rebels in South Africa to get military assistance", said the State's prosecutor.
The alleged plotters also promised to pay mercenaries with mining concessions.
Meanwhile, the US embassy in South Africa has confirmed that a US citizen was among 19 people who appeared in Court.
A spokesman for the US Embassy said the US citizen was identified as James Kazongo, a man with Congolese origins. It was unclear how he entered South Africa.
The other 18 plaintiffs are citizens of the DRC.
South Africa is home to close to 100,000 Congolese migrants, including refugees and is seen by analysts as fertile ground for opposition political parties to recruit members.