Khartoum: Thick plumes of smoke billowed into the sky Saturday as a fire ripped through Sudan's old presidential palace in the capital, Khartoum, an AFP journalist reported.

It was not immediately known if there were any casualties or what had caused the fire.

Police cordoned off the streets heading to the palace, built in 1832 on the bank of the Blue Nile, as smoke billowed from the building.

The palace was the official seat of the Sudanese government in the decades following the country's independence in 1956.

But in recent years, President Omar Al Bashir had shifted to a new palace from where he runs his administration's daily affairs.

The 75-year-old leader is facing a wave of angry protests against his iron-fisted rule of three decades, with demonstrators calling on him to step down.