Polling stations open across Brazil as President Luiz Inacio Lula da Silva casts his vote in Sao Paulo in the country's presidential runoff on Sunday.

Lula is seeking a fourth non-consecutive term in a closely contested presidential race against Senator Flavio Bolsonaro, the eldest son of former President Jair Bolsonaro.

The Workers' Party candidate is campaigning on strengthening workers' rights, raising living standards and expanding social programmes.

In the first round, Senator Flavio Bolsonaro narrowly topped the vote, securing 47.03% of valid votes against 45.16% for Lula.

Recent opinion polls point to a closely contested runoff, with surveys showing Bolsonaro at 51% of valid voting intentions and Lula at 49%, within the poll's two-percentage-point margin of error. Polling stations open as Lula votes in Brazil's presidential runoff.