By Martin Plaut
BBC Africa analyst

Thabo Mbeki wants to influence the choice of his successor

The African National Congresss has called on its branches to begin internal talks on who the party's candidate should be.

This is the starting gun for candidates to succeed President Thabo Mbeki to declare their hand.

The ANC will decide on its candidate at conference in December.

Whoever wins the party's nomination is almost certain to become the next president, as the ANC won nearly 70% of all votes in the last election in 2004.

Selection race

Mr Zuma has the support of the left in the ANC and the party's youth

Until now most candidates have kept a low profile. Only the ANC deputy president, Jacob Zuma, has declared he is willing to stand.

His supporters have been criss-crossing the country, trying to drum up support. But so too have President Mbeki's men.

Although Mr Mbeki cannot seek re-election as the country's president he wants to stay on as leader of his party - and influence his successor.

A leading Sunday newspaper says the president will back Joel Netshitenzhe, the head of the government's information service, and a key ally.

But other names are also in the frame. There is Tokyo Sexwale and Cyril Ramaphosa - two of the country's richest men - and the ANC's secretary general, Kgalema Motlanthe.

The selection race has begun, and promises to be the most seriously contested political event since the ANC came to power at the end of apartheid.