Brazilian President Luiz Inacio Lula da Silva has undergone surgery in São Paulo to drain a bleed on his brain linked to a fall at home in October.

The surgery was successful and the 79-year-old is "well" and being monitored in the intensive care unit, a medical note published by the government on Tuesday said.

Doctors will hold a press conference at 9am, local time, to provide further details.

Mr Lula underwent an MRI late on Monday in Brazil's capital of Brasilia after suffering a headache, which detected an intracranial haemorrhage. He was transferred to São Paulo for surgery at the Sirio Libanes hospital.

Mr Lula's fall in October also caused trauma to the back of his head that required stitches. 

Tests in early November showed his condition had remained stable.

The president's injury forced him to cancel a trip to Russia for a summit of the BRICS group of major emerging markets being held in Kazan, following medical advice to temporarily avoid long-haul flights

Reuters.