An earthquake measuring 5.3 on the Richter scale left 42 miners trapped 2,400m underground in a gold mine near the central South African town of Klerksdorp. Fourteen miners have so far been rescued. The fate of the other 28 is unknown.
The quake had its epicentre near the town of Stilfontein, 155km southwest of Johannesburg.
A police spokesman said at least 40 people were slightly injured in the towns of Klerksdorp and Stilfontein after the tremor struck.
The quake was thought to have been activated by mining operations.
Naturally-occurring earthquakes are rare in South Africa. The last major one, which occurred in 1969 north of Cape Town, measured 6.3 on the Richter scale and caused extensive damage.
