U.N. human rights spokeswoman Ravina Shamdasani said hospital medics had treated more than 60 people for gunshot wounds.
Zimbabwe was under an internet blackout on Friday after authorities extended a communications ban to cover emails, while the United Nations urged an end to a security crackdown on civilians triggered by days of deadly protests.
The government has said three people died during demonstrations that broke out on Monday after President Emmerson Mnangagwa raised fuel prices by 150 percent. Lawyers and activists say the toll was much higher and that security forces used violence and carried out mass arrests to quell the unrest.
In Geneva, The U.N. human rights office called on the government to stop the crackdown and denounced allegations of "generalized intimidation and harassment" of protesters.
As life returned to a semblance of normality in Harare, civilians ventured outside to stock up on food and other supplies while police continued to patrol the streets.
Jacob Mafume, spokesman for the main Movement for Democratic Change (MDC) opposition party, said he feared the web blackout was a prelude to more violence.
"The total shutdown of the internet is simply to enable crimes against humanity," he told Reuters. "The world must quickly step in to remove this blanket of darkness that has been put on the country."
Authorities have yet to respond to the allegations of a crackdown, but many Zimbabweans believe Mnangagwa is falling back on the tactics of his predecessor Robert Mugabe by using intimidation to crush dissent.
The president has also failed to make good on pre-election pledges to kick-start the ailing economy - beset by high inflation and a currency shortage, and the trigger for this week's protests.
Referring to allegations of night-time door-to-door searches against demonstrators and beatings by police, U.N. human rights spokeswoman Ravina Shamdasani said hospital medics had treated more than 60 people for gunshot wounds.
"This is not way to react to the expression of economic grievances by the population," she said.