President Jacob Zuma on Tuesday dismissed claims that South African troops deployed in restive Central Africa were protecting private business interests as "conspiracy theories."
Zuma is facing anger at home after 13 soldiers were killed and 27 wounded as rebels in the Central African Republic carried out a bloody coup a little over a week ago.
South Africa's heaviest military loss since apartheid has raised questions about the nature of the deployment, and prompted the opposition to demand an immediate pull out of the troops.
But at a memorial service for the soldiers, Zuma said his critics were "peddling various unfounded allegations and conspiracy theories."
"We reject any insinuation that these soldiers were sent to the CAR for any reason other than in pursuit of the national interest and the interests of the African continent.
"Our national servicemen died for a worthy cause. They died in defence of the country's foreign policy," said Zuma.
"They died defending our commitment to the renewal of the African continent, and to the promotion of peace and stability," he said.
The main opposition Democratic Alliance on Monday said it would submit an urgent parliamentary resolution to force Zuma to immediately withdraw the soldiers.
Zuma said that a contingent was sent to train local forces and provide protection for the now deposed Central African president Francois Bozize under a 2007 deal.
They were also to help refurbish military barracks and provide equipment.
When the situation in the Central African Republic deteriorated last year, it was decided to deploy an additional 200 troops to protect the trainers and their equipment.
Local media reports have suggested that the soldiers were sent to protect the business interests of certain South African politicians in the Central African Republic.