Al-Qaida's wing in North Africa has claimed responsibility for the January kidnappings of four tourists in northern Mali, including two Swiss nationals.
The Swiss foreign ministry said on Wednesday it was checking a report broadcast on Al Jazeera television.
The kidnapping case has top priority and Switzerland is cooperating with other countries to seek the swift and unconditional release of the hostages, according to a senior foreign ministry official.
Malian officials had initially blamed Tuareg rebels for abducting the Swiss couple, one German and one Briton near Mali's border with Niger on January 22. The tourists had been at a festival for Tuareg culture when they were taken from their car and driven to Niger.
The militant group also said it was behind the abduction of Canadian United Nations envoy Robert Fowler and his aide Louis Guay who went missing in Niger last December.
In an audio recording broadcast by the television channel the militants threatened to kill the hostages if demands are not met – adding that the group would soon issue its conditions.
Al-Qaida in the Islamic Maghreb, formerly known as the Salafist Group for Preaching and Combat (GSPC), has claimed a series of attacks in the region in recent years, including the kidnapping last year of two Austrian tourists abducted in Tunisia who were later freed in Mali.