"The main roads to town have been barricaded with rocks and there is no public transport carrying people", Phibeon Machona, a 27-year-old Epworth resident said.
Riot police in trucks patrolled downtown Harare while some shops remained closed.
Zimbabweans reacted with outrage Sunday to a sharp rise in fuel prices announced by President Emmerson Mnangagwa in a move to improve supplies as the country struggles with its worst gasoline shortages in a decade.
He said from midnight petrol prices would rise to $3.31 from $1.24 a litre and diesel prices to $3.11 from $1.36 a litre.
Teachers unions called a strike last week for better pay but their calls went largely unheeded.
The government has vowed it "will not hesitate to take action" against protesters who threaten to destabilise the country and the military was deployed to assist police.
Government doctors went on a 40-day strike beginning in early December demanding salaries in USA dollars and improved working conditions, while teachers' unions called a strike this week for better pay but their calls went largely unheeded.
As part of financial reforms, Zimbabwe also plans to re-introduce a local currency "in less than 12 months", after using the U.S. dollar and regional currencies since its hyperinflation crisis a decade ago.
While the Zimbabwean government insists the local bond note is equivalent to the USA dollar on a 1:1 ratio, on the parallel market the ratio is 1:3.2. Everyone was astounded by the rate of increase and the reason attached to this, as we are at a period where, globally, fuel prices are on a steady and healthy decline.
Although this will most certainly have an adverse effect on the way businesses respond to this, Mngangagwa, according to My Zimbabwe News, assured his people that the increase would not see price hikes in the retail environment. This government is trying to play with us. Crowds swelled as ordinary citizens joined with protesting activists to add their voices to the anti-fuel price demonstrations.
The government of Zimbabwe issued a statement condemning the riots as Western-sponsored acts.
Government has accused the strike organisers of pushing a political "regime change" agenda and of "subversive political activities". Media reports from Harare also said police conducted house-to-house searches looking for protesters.
The headquarters of the opposition Movement for Democratic Change Alliance was under police surveillance.
Following a de facto coup in November 2017 long-time ruler Robert Mugabe stepped down, and after a disputed election in July that saw Mnangagwa elected into office, the leader has promised an economic turnaround for the impoverished African nation.
Zimbabwe battles unemployment estimated at 90 percent.
The announcement comes ahead of Mnangagwa's tour of Eastern Europe and Switzerland to strengthen bilateral and economic ties.