Police said three people, including a member of the force, were killed during demonstrations which saw angry protesters block roads with stones and ransack and loot shops in major cities.
In response, residents in Zimbabwe said internet services had been cut off, with only those on virtual private networks enjoying continued access.
“The government in Zimbabwe should take action to ensure a free and open media environment, which means swiftly reestablishing internet and social media access,” CPJ Africa Program Coordinator Angela Quintal said.
“African governments too often use internet disruptions as a tool to stifle the free flow of news and commentary.”
In the letter to Zimbabwe’s minister of information communication technology and cyber security minister Kazembe Kazembe, the 20 organisations, including CPJ, Human Rights Foundation, Internet Sans Frontières, Reporters without Borders and the Right2Know Campaign, said internet shutdowns harmed human rights and economies.
“Shutdowns disrupt the free flow of information and create a cover of darkness that shields human rights abuses from public scrutiny,” the letter read.
“Journalists and media workers cannot contact sources, gather information, or file stories without digital communications tools.”
It urged the Zimbabwe government to encourage telecommunications and internet services providers “to respect human rights through public disclosures on policies and practices impacting users”.