Some have failed Zanu-PF, says Mugabe

Some officials had "failed" Zimbabwe's ruling Zanu-PF, President Robert Mugabe said on Thursday as he made an impassioned attack on Vice President Joice Mujuru and her allies.

Speaking to thousands of delegates as he opened Zanu-PF's congress, Mugabe, 90, said he felt "a deep sense of sorrow".

"As I greet you in the name of the politburo I must say... we have not behaved to you in a manner in which we should have behaved, a manner that was exemplary.

"Some of us failed you. As we thought we were working together, they were doing their own thing," Mugabe said in direct reference to Mujuru, who has set tongues wagging by her absence at the event.

Zanu-PF's messy power battles

"We should never send a thief to catch a thief."

Mujuru has been ousted from Zanu-PF's powerful central committee and looks almost certain to be demoted after 10 years as vice president.

The long-time president said even his wife Grace had celebrated when Mujuru was made vice president, then the first woman ever to hold the position in this southern African country.

In the last two months Grace Mugabe, 49, has been critical of Mujuru.

Grace Mugabe is almost certain to be elected head of Zanu-PF's women's league at this congress - and has not hidden her own presidential ambitions.

Analysts believe Mujuru had become a threat to Mugabe because of her popularity inside Zanu-PF, leading him to fear she could unseat him at this congress.

Mujuru's husband and chief backer General Solomon Mujuru was killed in a housefire in 2011. The Mujuru family says that the recent campaign against the vice president has revived their suspicions he was murdered as part of Zanu-PF's messy power battles.