Meanwhile, Emmerson Mnangagwa, incumbent president and ZANU-PF's leader, said on Thursday he was in talks with the opposition to find ways to defuse the situation.
For its part, ZANU-PF said it was "eagerly awaiting the announcement of the results" and appealed to the opposition "to ensure that their supporters maintain a calmness which existed when people went to vote".
FILE PHOTO: Supporters of the opposition Movement for Democratic Change party (MDC) of Nelson Chamisa, sing and dance in the street outside the party's headquarters following general elections in Harare, Zimbabwe, July 31, 2018.
The Zimbabwe Electoral Commission (ZEC) said Wednesday that of 210 parliamentary seats, 153 had been counted with ZANU-PF winning 110 and the MDC Alliance 41.
After first indicating it would release presidential vote totals on Wednesday, the electoral commission said it would wait until Thursday, adding that agents for the more than 20 candidates must verify them first.
Soldiers were on guard outside the headquarters of the ruling ZANU-PF party, while armored personnel carriers, water cannon trucks and police anti-riot vans drove through Harare sporadically pausing outside the MDC headquarters.
The hopes of a new chapter for Zimbabwe after years of violence and dissent are being dashed following the chaos that rocked the country on Wednesday killing at least three people.
A credible and peaceful vote was meant to end Zimbabwe's global isolation and draw in foreign investment to revive the shattered economy.
Zanu-PF leader Emmerson Mnangagwa called for calm in the wake of the protests and said he had reached out to Chamisa so the two could work together.
Protester, Colbert Mugwenhi said: "Why are the army here beating us?"
Longest lunar eclipse of the century set to arrive Friday
Do not forget to look up in the sky later this week because a historic lunar eclipse will be visible in South Africa. Since the moon will be at its most distant and smallest, it will take more time to cross the Earth's shadow.
Zimbabwe soldiers walk past a broken shop window in Harare on August 2 after election-related protests turned violent and resulted in three deaths.
The electoral roll has always been a contentious feature of Zimbabwean elections, allegedly the rotten core of systematic rigging under Mugabe.
Mnangagwa tweeted his condolences to the families of those killed a day earlier and affirmed his commitment to accountability, pledging to bring those responsible to justice through an "independent investigation".
Home Affairs Minister Obert Mpofu accused the opposition of using the presence of worldwide election observers to "grandstand" and cause "anarchy".
The EU observer mission said "a truly level playing field was not achieved" in the election, pointing out the "misuse of state resources, instances of coercion and intimidation, partisan behaviour by traditional leaders and overt bias in state media".
Protesters surrounded vehicles belonging to the observer missions as they passed through downtown Harare.
"Yesterday's events leave ordinary citizens with serious doubts that this government is any different from its predecessor, if not worse", the forum said, referring to the long rule of Mugabe, who resigned in November under military pressure.
Under Mugabe's 37-year reign, elections were often marred by fraud and deadly violence.
Mahama urges the prompt release of presidential results from Monday's election, saying delays will increase speculation that results were manipulated. "They are there to assist the police".