The al-Qaeda group says it seized Frenchman Pierre Camatte in Mali
An offshoot of the al-Qaeda network has reportedly said its members kidnapped three Spanish aid workers in Mauritania and a Frenchman in Mali last month.
A spokesman for al-Qaeda in the Islamic Maghreb made the claim in an audio recording to the al-Jazeera TV station.
There has been no sighting of the four Europeans since the kidnappings, which took place within days of each other.
The same group is believed to be behind the murder of British hostage Edwin Dyer in June.
Pierre Camatte, 61, was taken from his hotel by gunmen in Menaka in Mali on 25 November, while Albert Vilalta, 35, Roque Pascual, 50, and Alicia Gamez, 35, were snatched from an aid convey near Mauritania's northern city of Nouadhibou on 29 November.
In the audio recording, al-Qaeda spokesman Saleh Abu Mohammad said his organisation had "managed to kidnap four Europeans in two distinct operations".
He added that the group would contact France and Spain at a later date with its demands, but gave no further details about what these were, AFP reported.
Spain's Foreign Minister Miguel Angel Moratinos said his government was investigating the authenticity of the claim.
His colleague Interior Minister Alfredo Perez Rubalcaba had previously said he believed an al-Qaeda cell was responsible for the kidnapping.
The UK recently warned its nationals not to visit northern Mali because of the threat of attack by the North African branch of al-Qaeda.
In June this year an American teacher was killed in Mauritania, with al-Qaeda later claiming it had killed him for spreading Christianity in the Islamic state.