Well-known South African journalist Angela Quintal appealed for help on Facebook on Wednesday, saying she was being taken for interrogation in Dar es Salaam, Tanzania.
Quintal, a former editor and now Africa Programme Coordinator at Committee to Protect Journalists (CPJ) issued this message:
"SOS we are being taken away for interrogation in Dar [es Salaam]. We don't know why. Taken away from Southern Sun Hotel."
It was not immediately clear who she was with.
The CPJ is an independent, non-profit organisation that promotes press freedom worldwide and defends journalists' rights to report freely.
In the meantime, the Department of International Relations and Cooperation is trying to establish what has happened.
Spokesperson Ndivhuwo Mabaya said he had just called Dirco's operations room and was contacting South Africa's ambassador in Tanzania.
"I am also trying to get hold of her [Quintal] to find out what is happening," he said.