Harare - Zimbabwe's army chief on Monday demanded a "stop" to the purge in the ruling Zanu-PF party after the sacking of vice president Emmerson Mnangagwa, and warned the military could intervene."The current purging which is clearly targeting members of the party with a liberation background must stop forthwith," General Constantino Chiwenga told a media conference attended by about 90 senior army officers at army HQ.In an unprecedented warning, he said in a statement: "We must remind those behind the current treacherous shenanigans that when it comes to matters of protecting our revolution, the military will not hesitate to step in."Mnangagwa was dismissed and humiliated a week earlier after clashing with veteran President Robert Mugabe's wife Grace, who is now in prime position to succeed her 93-year-old husband.Analysts had warned that the sacking would spark repercussions beyond Mugabe's control.Mnangagwa's main rivals within the ruling Zanu-PF party are the younger "Generation 40" or "G40" group, who enjoy Grace's support.But the 75-year-old former vice president has powerful military connections, having served as defence and state security minister.Soon after his dismissal Mnangagwa quickly fled into exile, vowing to return and launched a direct challenge to Mugabe by calling for members of the ruling party to desert the president.Mnangagwa - whose nickname is the "Crocodile" - defiantly told Mugabe that the party was "not personal property for you and your wife to do as you please".Mugabe then reacted by expelling his long time confidante and former liberation war guerrilla, from the party. 'Democratic rights' Zanu-PF is due to hold a congress next month, when 52-year-old Grace, a hugely divisive figure, could be appointed as one of the country's two vice presidents.The move could pave the way for her to get the top job after Mugabe.Mugabe, the world's oldest president, is showing increasing signs of old age, but has refused to name his successor.Zimbabwe goes to elections next year to vote for a president and lawmakers.Chiwenga urged unfettered participation at the party's December special congress to choose new leaders."Members must go with equal opportunity to exercise their democratic rights," he said.Chiwenga charged the ruling Zanu-PF party had been infiltrated by people who were seeking to destroy it from within."Known counter-revolutionaries... must be exposed and fished out," he said.The purging in the party had plunged the country into a crisis, he said.Chiwenga called on the ruling party officials to "stop reckless utterance... denigrating the military, which is causing alarm and despondency within the rank and file".The army boss said the infighting in the party had impacted the country, which is reeling under an economic crisis."There is distress, trepidation and despondence within the nation," he said."As a result of the squabbling, there has been no meaningful development in the country for the past five years."The crisis had resulted in "cash shortages and rising commodity prices," he said.Zimbabwe in 2009 abandoned its own currency in favour of the US dollar due to hyperinflation.But it started running out of those dollars and last year it introduced "bond notes", a parallel currency pegged to the US dollar.The bond notes themselves are running short, forcing banks to ration cash withdrawals.