The internet had been partially restored after a first shutdown started on Tuesday.
“We were served with another directive for total shutdown of the internet until further notice,” Econet, the country’s biggest provider, said in a text message on Friday.
“Our lawyers advised we are required to comply with the directive pending the court decision on its legality. The earlier directive(s) are already the subject of pending high court application.
“We sincerely apologise for all inconveniences caused by the acts of government.”
The EU on Thursday joined the US and Britain in criticising the authorities’ response to the protests.
“The escalation of violence in Zimbabwe over recent days has been aggravated by the disproportionate use of force by security personnel,” European Commission spokeswoman Maja Kocijancic said in a statement.
“The shutdown of access to the internet should also be reversed.”
The US embassy in Harare it was “alarmed by credible reports that security forces are targeting and beating political activists and labor leaders”.
Nationwide demonstrations erupted on Monday after President Emmerson Mnangagwa announced that fuel prices were being doubled in a country suffering regular shortages of fuel, food and medicine.
Mnangagwa, who succeeded ousted authoritarian president Robert Mugabe in 2017, had promised a fresh start for Zimbabwe after decades of repression and economic decline.
Trade unions called the national strike on Monday and the demonstrations took place in several cities with widespread rioting and looting.
Security forces have made about 600 arrests.
Police and soldiers have been accused of indiscriminately dragging people from their homes and beating them.