I read about it first on the German Land Rover forum, about an Austrian couple, which went missing since 18. February while on a journey by Land Rover through the Tunesian desert.
Now the (almost) worst worries have been confirmed:
They have been kidnapped by the Maghreb branch of Al Qaeda and have been possibly brought to the Saharan part of Mali.
So far Tunesia was considered to be a relatively safe country, living largely from tourism, but it seems that Al Qaeda considers any western foreigner to be a target (didn't they always?) to destroy the Tunesian tourism industry.
The Austrian government has urged the governments of Tunesia, Algeria and Mali not to undertake any military actions against the kidnappers.