Nineteen suspected Congolese rebels have been charged in a South African court with plotting a coup against President Joseph Kabila.
Prosecutors said the men belonged to the Democratic Republic of Congo's Union of Nationalists for Renewal (UNR) rebel group.
South Africa's counter-terrorism forces arrested them earlier this week in the northern Limpopo province.
DR Congo has been hit by rebellions throughout Mr Kabila's rule.
He took power in 2001, following the assassination of his father, Laurent Kabila.
One of the suspected coup plotters has been identified as US citizen James Kazongo, AP news agency reports.
"South African authorities got in touch with our consular officers, who have visited him. We have been in touch with him and communicated with his family and provided consular services," US embassy spokesman Jack Hillmeyer told AP.
The suspected rebels entered South Africa to organise "specialised military training" to overthrow Mr Kabila, prosecutor Shaun Abrahams told the Pretoria Regional Court, AFP news agency reports.
They had also promised to "pay mercenaries with mining concessions" in resource-rich DR Congo, Mr Abrahams said, it reports.
South African police received a tip-off about the presence of the group last September and infiltrated it, he is quoted as saying.
There are numerous different armed groups mainly operating in eastern DR Congo.
The area has most recently been affected by a rebellion by the M23 rebel group which has forced 800,000 people from their homes.