Before his sack, Mnangagwa, aka Crocodile, defiantly told Mugabe that the party was "not personal property for you and your wife to do as you please".
Several military tanks and trucks were spotted heading towards the Zimbabwean capital Harare Tuesday, prompting fears of a possible coup or show of power by the army.
"Folks our nation is in a unsafe place", anti-government activist pastor Evan Mawarire wrote on his Twitter account.
Despite the reports of the tanks, Zimbabwe's ruling party Zanu PF took to Twitter to deny rumours of a coup.
On Monday, the commander of Zimbabwe Defence Forces said he was prepared to "step in" to end a purge of supporters of a vice president sacked last week.
President Robert Mugabe's famous "blue house" or "blue roof" has been sealed off by heavily armed military personnel, Khuluma Afrika has confirmed.
Chiwenga on Monday issued a hard hitting statement urging the ruling party to stop expulsion of party members with a liberation war background.
Political analysts however say the military stayed quiet then because the beneficiary of Mujuru's downfall was the 75-year-old Mnangagwa, a war veteran. President Mugabe, however, is not at the house as we speak, and Khuluma Afrika was able to confirm that his motorcade is still at his Munhumutapa offices in the capital.
The party appears split over the succession with the G40 faction supporting Grace and another faction, that includes war veterans, rooting for the ousted Mnangagwa.
"He is in a corner".
"What we are witnessing is the military saying: "We are willing to intervene if the red line is crossed".
She is now expected to be appointed vice-president at a special Zanu-PF congress next month.