Updated at 3:15 p.m. ETZimbabwe's governing ZANU-PF party voted Sunday to remove President Robert Mugabe and appoint ousted Vice President Emmerson Mnangagwa to replace him. The move marked a major turn in nearly four decades of the 93-year-old's sometimes brutal and tyrannical rule.But in an address broadcast on state television Sunday night, which some observers had predicted Mugabe would use to announce his resignation, a defiant Mugabe clung to power, saying he will oversee a congress meeting in a few weeks."I will preside over its processes, which must not be prepossessed by any acts calculated to undermine it or to compromise the outcomes in the eyes of the public," Mugabe said.But earlier Sunday, ZANU-PF said Mugabe has until midday Monday to step down and if he refuses parliament will step in."If Mugabe is not gone by Tuesday, then as sure as the sun rises from the east, impeachment process will kick in," a member of opposition party MDC-T Innocent Gonese told the AP.In his Sunday night address, Mugabe said the way forward cannot be through "vying cliques that ride roughshod over party rules and procedures." Instead, he called for a return "to the guiding principles of our party as enshrined in its constitution."But earlier Sunday, videos posted to social media on showed members of ZANU-PF breaking into cheers as well as song and dance,following their vote to oust the world's oldesthead of state.And in a major show of unity one day earlier, thousands of Zimbabweans took to the streets of the capital, Harare, to demand that Mugabe go. The Associated Press reports, the protest itself was a demonstration of just how much things have changed in Zimbabwe as the protesters would have faced a police crackdown just days earlier.The ruling party also voted Sunday to dismiss Mugabe's unpopular wife Grace. "Without the military's intervention, first lady Grace Mugabe likely would have replaced Mnangagwa as vice president and been in a position to succeed her husband," The AP reports.But questions abound about a Zimbabwe under the rule of Mnangagwa, a man who has earned the nickname of "The Crocodile." As NPR's Ofeibea Quist Arcton has reported: