The contest pits Vice-President Joice Mujuru - who took the name of Teurai Ropa, or ''Spill Blood'' in the Shona language, when as a teenager she joined the fight for independence - against Defence Minister Emmerson Mnangagwa, who at 19 led a sabotage unit known as the ''Crocodile Gang''.

''The succession issue remains a challenge to the party,'' Patrick Chinamasa, a politburo member of Mr Mugabe's Zimbabwe African National-Patriotic Front and justice minister, said.

''We are fully cognisant of the divisive nature of the succession issue. We need to deal with it without losing cohesion.''

With the backing of many in the armed forces, intelligence and police chiefs, Mr Mnangagwa would probably focus on keeping military leaders in control of diamond fields and some of the best farmland, analyst Mark Rosenberg said.

Ms Mujuru may seek to repair relations with the international community to boost her faction's investments in banking and retail, he said. ''Mujuru and her allies are vested in industries like finance, retail and hospitality that demand more rational policies to grow,'' Mr Rosenberg said.

Mr Mugabe won the July 31 presidential race with 61 per cent of the vote, which his opponent Morgan Tsvangirai described as a ''farce'' because of alleged rigging.

His Movement for Democratic Change has submitted a court challenge in Harare against the results, saying 870,000 names were duplicated on the voters' roll. It called for a fresh election within 60 days.

In a speech on Monday, Mr Mugabe said critics of the win could ''go hang''. ''If they cannot stomach it, they can go and hang. If they die, even dogs will not sniff at their corpses. Never will we go back on our victory.'' After casting his vote, Mr Mugabe said he would serve out his term.

There are ''too many tensions and divisions for Mugabe to step down'', International Crisis Group researcher Trevor Maisiri said. ''The succession battle is going to be more intense than it was before.''

Ms Mujuru and Mr Mnangagwa have been in Mr Mugabe's cabinet since independence in 1980.

Mr Mnangagwa was the chief of intelligence when Mr Mugabe ordered the North Korean-trained Fifth Brigade to crack down on rebels in the south-western region of Matabeleland in the 1980s, resulting in the death of as many as 20,000 from the Ndebele ethnic minority. Legally, Ms Mujuru, 58, is first in line to succeed Mr Mugabe.

''She represents the gentler mode of contemporary politics - unifying, motherly, compassionate and national,'' Ibbo Mandaza, a former Mujuru adviser said.

Mr Mnangagwa, 66, is the chief of the joint operations command. Mr Mandaza said he was ''the typical strongman and therefore likely to be very ruthless''.

Mr Rosenberg said Mr Mnangagwa could draw on the support of figures including Zimbabwe Defence Forces commander Constantine Chiwenga, head of police Augustine Chihuri and Happyton Bonyongwe, who runs the Central Intelligence Organisation.

Bloomberg