Harare, Nov 20 (IANS): Zimbabwe's embattled President Robert Mugabe, who was stripped of the ruling party's leadership a day earlier, is facing a deadline to resign after a surprise speech in which he refused to quit.

The ruling Zanu-PF has said it will impeach Mugabe if he does not step down by 12 p.m. on Monday. Proceedings could begin as soon as Tuesday when Parliament meets.

Mugabe's grip on power has weakened since the Army intervened on Wednesday in a row over who should succeed him.

The crisis began two weeks ago when the 93-year-old leader sacked his deputy Emmerson Mnangagwa, angering Army commanders who saw it as an attempt to position his wife Grace as next President.

Zimbabwe has since then seen huge street rallies with demonstrators, including the country's influential war veterans, demanding his immediate resignation.

During the 20-minute address, Mugabe, who was flanked by generals, made no mention of the pressure from his party and the public to quit, the BBC reported.

Instead, he declared that the military had done nothing wrong by seizing power and placing him under house arrest.

"Whatever the pros and cons of how they (the Army) went about their operation, I, as Commander-in-Chief, do acknowledge their concerns," he said, in reference to the Army's move last week to take over the state broadcaster in the capital Harare.

He also said "the (Zanu-PF) party congress is due in a few weeks and I will preside over its processes".

Before Mugabe's speech, Mnangagwa was named as Zanu-PF's new leader and candidate for the 2018 general elections, while Mugabe's wife was expelled.

After Mugabe's speech, Zanu-PF chief whip Lovemore Matuke was quoted as saying that the resignation ultimatum was unchanged.

He added that impeachment proceedings could be launched on Tuesday in Parliament. This would require a two-thirds majority in both chambers.