National Defence Force (NDF) spokesman brigadier general Kwena Mangope said that it "is assumed that there was a mechanical problem, which led to the accident. The gun, which was fully loaded, did not fire as it normally should have."

"It appears as though the gun, which is computerised, jammed before there was some sort of explosion, and then it opened fire uncontrollably, killing and injuring the soldiers."

The NDF are now investigating if the cause of the failure was due to errors in the software.

But a pessimistic note was sounded by defence expert Helmoed-Römer Heitman, who believes that if "the cause lay in computer error, the reason for the tragedy might never be found."

According to defence engineer and entrepreneur Richard Young, this is not the first time that a computerised or so-called 'smart' weapon has malfunctioned on South African soil.

Young's company C2I2 were commissioned by the SA government to deliver two air defence artillery upgrade programmes during the '90s.

“I personally saw a gun go out of control several times,” said Young, referring to shooting trials at the state-run Alkantpan shooting range.

“They made a temporary rig consisting of two steel poles on each side of the weapon, with a rope in between to keep the weapon from swinging. The weapon eventually knocked the poles down.”

Young attributes the problems with smart weapons to the SA defence force's acquisitions agency, Armscor.

In the '90s, Armscor would allocate money on a yearly basis, resulting in programmes that were often rushed.

“It would not surprise me if major shortcuts were taken in the qualification of the upgrades," Young said.

"A system like that should never fail to the dangerous mode, except if it was a shoddy design or a shoddy modification."