- Video report by ITV News Africa Correspondent John Ray
Zimbabwe's ruling party has instructed its chief whip to move ahead with impeachment proceedings against President Robert Mugabe, after he resisted calls to step down, an official said.
Mugabe was also formally notified that he has been fired from his position as party leader.
ZANU-PF party spokesman Simon Khaya Moyo said in a statement that Mugabe was notified this morning of the decisions taken by the party's Central Committee a day earlier.
He added impeachment will begin when the country's parliament meets on Tuesday, and the 93-year-old Mugabe could be gone by Wednesday.
The party's deputy secretary for legal affairs Paul Mangwana has said the main charge against Mugabe is "allowing his wife to usurp government powers" and that "he is too old and cannot even walk without help".
The ruling party ZANU-PF will need the backing of the MDC opposition to have enough votes in parliament but Mangwana said they will be supportive to the action.
Defiant Mugabe ignored a deadline of midday on Monday (10.00GMT) to resign after the party voted to sack him.
Instead, Mugabe said in a televised statement that he would preside over the ZANU-PF party conference in December. He has also called a cabinet meeting for Tuesday morning.
Zimbabwe's war veterans' association leader Chris Mutsvangwa said the military should step back and let the people, and politics, remove longtime President from power and warned of protests taking place.
Students have begun to gather at the University of Zimbabwe campus in Harare to call for the President and his Vice Chancellor Levi Nyagura to step down.
He told a press conference on Monday that Mr Mugabe should announce his departure immediately and let the country "start a new page".
"We are saying 'Mugabe, go now, go now," he said. "Your time is up."
"You should have the dignity and decency to spare the country of further turmoil by simply announcing your departure immediately."
The war veterans' association will go to court to argue that Mr Mugabe is "derelict of his executive duty", Mr Mutsvangwa said.
Some ruling party members said an impeachment process likely would not lead to Mr Mugabe's immediate resignation and could take days to complete.
Calls for the President to resign came following his decision to fire vice-president Emmerson Mnangagwa, and the positioning of the unpopular first lady, Grace Mugabe, to replace him and probably succeed her husband as leader.
The congress is expected to ratify his firing as party chief and the the expulsion of the unpopular first lady and name Mr Mnangagwa to replace him.
Mr Mugabe, who has ruled as President for 30 years and previously as Prime Minister, is largely confined to his private home by the military.
He has discussed his possible resignation on two occasions with military commanders after they effectively took over the country last Tuesday.
But speaking on Sunday, Mr Mugabe insisted he remained their "commander in chief" and President.
Seated at a table in State House, Mr Mugabe said that "failures of the past" may have triggered anger "in some quarters, which he called "quite understandable".
Opposition leader Morgan Tsvangirai released a statement saying that he doubts the ability of the ruling party to solve the country's challenges.
He said ZANU-PF has been hurt by factional battles and that it appears to have differences with the military over how to handle the confusing situation.
Africa minister Rory Stewart said the end of the "brutal tragedy" of Robert Mugabe's rule in Zimbabwe could transform the country.
But he warned his departure cannot be taken for granted.
"Nothing with Mugabe is inconceivable," he said. "He clearly wants to hang on as late as December, which is the party congress."
He said Mr Mnangagwa was trying to take power in a way that was "constitutional and legal" as he wanted to be seen as legitimate which could give the opportunity of fair elections.
But he acknowledged it was right to be "sceptical" of Mr Mnangagwa, the politician nicknamed the Crocodile who was at Mr Mugabe's side for much of his time in office but he said it could be a "time for change".
"This is one of the most educated populations in Africa, it has got fantastic potential in its natural resources and if Zimbabwe set off on a better path, if its economy recovered, if it genuinely had some political freedom, that would have an incredible ripple effect across the region and be a huge example for Africa," said Mr Stewart.
"The critical question is whether he is just going to be replaced by another Zanu-PF stitch-up or whether genuinely the constitution will be respected and free elections will happen next year."
Downing Street appealed to all sides to refrain from violence and called for a swift resolution to the situation.