Global election observers earlier called for the result of the presidential vote to be released as soon as possible to ease tensions, saying delays will add to any speculation the result was manipulated.
The Zimbabwe Electoral Commission's decision to delay announcing the results of the presidential race at least until Thursday - three days after the vote - seemed certain to bring more opposition anger if President Emmerson Mnangagwa is declared the victor.
Grandmother Sylvia Matambo, from Harare's Waterfalls suburb and an employee of Zimbabwe National Water Authority, died after she was caught in crossfire and shot in the back.
He accused the commission of releasing the parliamentary results first to prepare Zimbabweans for a Mnangagwa victory.
Soldiers and police have cleared the streets of central Harare today.
Three people were killed after soldiers moved into Harare on Wednesday, firing live rounds and beating protesters.
When Zec announced that Zanu-PF had won the parliamentary vote by a landslide on Wednesday, things turned nasty.
He said police arrested several of his MDC colleagues and seized computers. A credible vote is crucial to the lifting of the sanctions so that the collapsed economy can recover.
"The more the presidential vote is delayed, the more it calls into question the population's confidence in the election process", said former Liberian leader Ellen Johnson Sirleaf, the lead observer of a US monitoring mission.
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".
Mnangagwa previously said the opposition was to blame for the violence, though some global observers criticized the military for opening fire on unarmed civilians.
Almost all shops in downtown Harare were shuttered and the normally bustling pavements quiet the day after the bloodshed.
The US embassy in Harare urged the army to "use restraint" on Twitter, saying the country had an "historic opportunity" for a brighter future.
Before the police stormed the MDC headquarters, Secretary General Douglas Mwonzora said 27 party workers carrying out voter tabulation were locked inside its offices as police sealed them off on Thursday.
UN Secretary General Antonio Guterres urged Zimbabwe's politicians to exercise restraint, while United Kingdom foreign office minister Harriett Baldwin said she was "deeply concerned" by the violence. He says the situation on the ground remains tense and talks about the outcome of the election commission press conference.
Members of the Movement for Democratic Change (MDC) party are claiming that the elections have been rigged.
The military deployment was the first time that soldiers had appeared in the capital's streets since a military takeover led to the ouster of Mugabe in November. After nightfall, soldiers patrolled streets, where eight months ago thousands had celebrated Mr. Mugabe's overthrow as a new "independence day" for the country.
Some Harare residents expressed frustration and exhaustion at the violence. "We need security for the people".
Zanu-PF, which has been in power for 38 years, including the 37-year tenure of Robert Mugabe, has denied any rigging.
This invitation of formerly banned election observer missions had, according to Augusto, demonstrated "transparency and confidence building in Zimbabwe's electoral process".
Another resident, 29-year-old Sifas Gavanga, said: "We are a peaceful nation".