Speaking to News24 on Thursday morning, spokesperson Ndivhuwo Mabaya said that while there is still much uncertainty about her detention, she and her colleague, Muthoki Mumo were returned to their Dar es Salaam hotel at around 03:00 on Thursday.
"Officers who identified themselves as working with the Tanzanian immigration authority detained Quintal and Mumo in their hotel room in Dar-es-Salaam", CPJ said in a statement.
There were concerns after it emerged that South African journalist Angela Quintal, Africa programme coordinator for press freedom group the Committee to Protect Journalists (CPJ), and her Kenyan colleague Muthoki Mumo had been detained by authorities on Wednesday evening without explanation.
The International Relations Department says they have since been released, but details of exactly what transpired are still unclear.
"We continue to engage with our Government of Tanzania counterparts on a wide range of issues, including those related to human rights", the State Department said in a statement Wednesday.
Dirco confirm safety of journalists in TanzaniaAngela Quintal: What happened?
Mabaya said she was unable to locate it and her Twitter and Facebook profiles remain deactivated.
"We need to understand the circumstances. They were in the country on a reporting mission for CPJ". "We believe the arbitrary detention of journalists is a direct and unsafe threat to media freedom and access to information". "Quintal and Mumo were then escorted from the hotel and. taken to an unknown location".
On Thursday, CPJ's executive director Joel Simon said the journalists' mobile phones may have been compromised.
Tanzanian Authorities took their passports upon arrest, and are yet to return them.