Two Italian citizens seized in Niger after an ambush on their off-road touring group are being held by rebels, one of the pair told his wife by phone.
The tourists were travelling through desert in off-road vehicles
Claudio Chiodi called to dictate a statement saying he and a second man were being held not for ransom but for political reasons.
He named the group as the Revolutionary Armed Forces of the Sahara (Fars).
Twenty other tourists were released by the gunmen after the desert ambush on Monday, in which nobody was hurt.
The freed tourists, 18 Italians, a German and a Brazilian, have continued on their way across the West African country to the Algerian border.
Federica Franzoni, wife of Mr Chiodi, said her husband had told her that he and Ivano de Capitani were in good health and being treated well.
The statement he read to her contained a warning to tourists to avoid the area until "the situation with the Niger government has been cleared".
"Those people who do not respect this condition will be captured at their own risk," it added.
The group, which is believed to be largely made up of Tubu tribespeople, said it was "laying claim to Niger territory".
Giovanni Davoli, an Italian diplomat in the capital, Niamey, said Niger's security services were "well on the trace" of the kidnappers.
"Of course our priority is to save the life of our citizens," he told Reuters news agency.
A blog kept by Mr Chiodi and others tells how the group survived an encounter with armed men on Monday 14 August.
On that occasion, they were confronted by a group of men armed with rifles and a bazooka.
"Only the intervention of our guide... succeeded in resolving the situation," Mr Chiodi wrote.
The area near Lake Chad where the party was ambushed is notorious for banditry.
Three years ago, more than 30 European tourists were captured by suspected militant Islamists in the border region of Niger and Algeria.
They were rescued in an operation by the Algerian military.