Firefighters were battling a blaze on the sixth floor of the headquarters of South Africa's ruling African National Congress (ANC) today, Johannesburg emergency services spokesman said.
"It's not clear at this stage how it started but we suspect it was at the air conditioning plant around 2 o'clock (1pm Irish time) this afternoon," spokesman Malcolm Midgley said.
The ANC secretary general and his deputy's offices are on the sixth floor of Luthuli House which also has offices of South Africa's President Thabo Mbeki and his recently fired deputy in their capacity as ANC elected officials.
The building was the venue of Thursday's meeting between the ruling parties and its alliance partners to patch up widening rifts over the dismissal of Zuma. It is also the venue of regular meetings by ANC leaders.
ANC spokesman Steyn Speed said no one was injured and that he was still unaware of the extent of the damage.