Sao Tome and Principe President Evaristo Carvalho has been hospitalised since Saturday following an illness.
Local media confirmed that the president is admitted to Dr Ayres de Menezes Hospital.
VOA radio quoted sources saying that the head of state was operated on for an umbilical hernia.
The president’s hospitalisation comes at a time when the country is experiencing an electoral crisis due to the delay in holding the second round of the presidential elections.
President Carvalho is not a candidate and his term ends on September 3, 2021.