President Cyril Ramaphosa will, reportedly, attend an urgent meeting regarding the stand-off between Isis-linked militants and Mozambican forces.
Militants from the al-Shabaab group have taken control of Palma in the Cabo Delgado province in northern Mozambique.
When the siege began on Wednesday, hundreds of people fled to a nearby hotel where they are still trapped.
At least seven people, including one South African, are believed to have been killed in the attack, with many more unaccounted for.
