The 19 alleged Democratic Republic of Congo (DRC) rebels arrested in South Africa were to get training to oust President Joseph Kabila's government, the prosecution said on Wednesday.
It said there was no indication at this stage that the group had any links to the M23 rebels who have been fighting the DRC government army since May last year in the country's volatile eastern Kivu region.
"The grouping's objective was to receive specialised military related training to overthrow the current DRC government," National Prosecution Authority spokesman Makhosini Nkosi said in a statement received on Wednesday.
The suspects were arrested by a South African elite police unit in a remote area north of the country in a dawn raid on Tuesday.
Nkosi told AFP the group will appear in court on Thursday on charges of breaching South Africa's Foreign Military Assistance laws and will be extradicted to their home country after the trial.
Further arrests are likely, but no South African nationals are thought to be involved in the offence.
The DRC government spokesman, Lambert Mende, on Tuesday said Kinshasa had been informed of the arrest of the 19 alleged plotters.
"They were arrested just as they wanted to take action".
"Contacts have been established to see what would be the best step: either they are tried in South Africa, or they are deferred before a Congolese court. The ministry of justice is working on it and will recommend to us the best procedure," Mende told AFP.
He added that "at this stage", his government could not say whether the suspected rebels belonged to M23.