Zimbabwe’s Movement for Democratic Change, led by Thokozani Khupe, criticised the army’s "heavy handedness" during violent protests in the capital Harare that claimed at least three lives on Wednesday.
In a statement, MDC-T spokesperson Linda Masarira said the party condemns the harsh actions of the army against the "unarmed" nature of citizens.
"We condemn the heavy handedness of the army given the unarmed nature of our citizens. The right to demonstrate is enshrined in section 59 of the constitution, we implore the police to deal with unruly elements by arresting them.
"We are equally shocked by the untimely loss of human life in a matter that could have simply been resolved by the legal remedy platforms available," he said.
The break-away party also deplored the action taken by MDC Alliance and the failure to maintain peaceful demonstrations.
According to AFP, the government late on Wednesday vowed to enforce a security crackdown to prevent further unrest after the army opened fire to disperse opposition protests in Harare.
Monday's polls - the first since autocratic president Robert Mugabe was forced out by a brief military takeover in November - was seen to turn the page on years of violence-marred elections and brutal repression of dissent.
However, the mood quickly descended into anger and chaos as supporters of the MDC Alliance opposition declared they were being cheated in the election count.
MDC supporters, who say their leader Nelson Chamisa won the vote, burnt tyres and pulled down street signs as protests spread from the party headquarters in Harare.
Police confirmed the death toll of three, and Mnangagwa issued a statement blaming the opposition for the unrest and fatalities.
Official results on Wednesday showed that the ruling Zanu-PF party had easily won most seats in the parliamentary ballot - strengthening President Emmerson Mnangagwa's prospects of holding onto power in the key presidential race.
"We call upon Zimbabwe Electoral Commission to exercise its mandate by ensuring that presidential results are announced within the specified 5 day time frame," said Masarira.
It also called on the MDC Alliance to respect the ZEC process and allow the electoral process to get to its logical conclusion.
"We also advise the MDC Alliance to respect the ZEC process with the deportment it deserves and allow the electoral process currently underway to get to its logical conclusion," added Masarira.