President Robert Mugabe’s increasingly powerful wife Grace has threatened Zimbabwe’s vice president with expulsion from the ruling party, throwing a fierce succession battle into the open.

But the first lady said she is not angling for Vice-President and one-time Mugabe heir apparent Joice Mujuru’s post although she used the war “war” in a rally.

“I told the President that if you don’t dump that faction leader we will dump her ourselves,” Grace Mugabe said on the campaign trail, referring to Mujuru.

Mujuru and powerful Justice Minister Emmerson Mnangagwa — who in the past controlled the secret police and military — are seen as the leading contenders to replace 90-year-old Mugabe when he steps down or dies.

But Grace Mugabe’s recent entry into politics, swift rise to power within the ruling ZANU-PF and ferocious attacks on Mujuru, have raised the prospect that the vice president’s star is waning.

It has also raised speculation that Mugabe could be grooming his wife to take over when he dies.

“We campaigned for you (Mujuru) not only last year, but over the years, but now it is war because I have been nominated,” said Grace Mugabe, 49, who is set to become head of ZANU-PF’s influential women’s league.

“I never said I want anyone’s position” she told party supporters at her final rally in Marondera, east of the capital, on Friday.

Grace Mugabe accused Mujuru — the widow of the late liberation war army commander Solomon Mujuru — of leading a faction vying for power, and demanded she apologise.

“You cannot continue denying that you lead a faction every day. Wherever you are, go together with your cronies, go and apologise before it is too late because the President is also fed up,” Grace Mugabe said.

She also accused Mujuru of supporting the opposition.