Zimbabwe - Infighting within Zimbabwe's ruling party has reached such a peak that soldiers, police and intelligence agents are now taking sides, President Robert Mugabe said on Friday. Mugabe, 91, made an impassioned plea for unity in Zanu-PF at the opening of a party conference in Victoria Falls. Up to 6 000 party delegates are packed into a tent in the sweltering heat of Zimbabwe's best-known tourist resort for this key event.Speaking in Shona and English, Mugabe said that it was "not right" that soldiers and police were involved in the factional fights. His quotes were translated by the official Chronicle newspaper. "They should stop it," Mugabe added. "Stop it" is one of the phrases Mugabe's wife has become famous for.Flanked by Grace, 50, the longtime Zimbabwean leader said there were "ambitious people" who wanted power in Zanu-PF. That did not seem to be a reference to his wife, who denies claims that she is angling for the presidency. Not everyone believes her. At the moment the first lady's supporters appear to be mainly pitted against those who back vice president Emmerson Mnangagwa for president in the event of Mugabe dying or stepping down. Grace Mugabe led the campaign to get the popular Joice Mujuru ousted from the vice presidency this time last year.Mugabe says there will be no changes in party leadership at this conference despite speculation to the contrary. Several Xanu-PF officials have been expelled or suspended ahead of the gathering.The Zimbabwean president also hit out at new black farmers whom he said were being used as "fronts" for whites. Up to 4 000 white farmers have lost their land since Mugabe launched a land reform programme in 2000. A number are now quietly leasing land back from the new owners.The conference is being screened on national TV.