Zimbabwe's ruling party has started a key congress at which President Robert Mugabe is poised to consolidate his grip on power by appointing a new set of loyalists, including his wife Grace.

Grace Mugabe is set to take over as the head of the ZANU-PF party's women's league at the conference, which began Tuesday and will last for several days. Mugabe's wife has increasingly criticized Vice President Joice Mujuru, whose political influence has waned. Party officials seen as allies of Mujuru have been stripped of their posts.

The state-run Sunday Mail newspaper alleged that Mujuru was involved in an assassination plot against the 90-year-old Mugabe. Mujuru, a member of Mugabe's inner circle since the 1970s independence war, denied the allegations, saying she was prepared to defend herself in court.