"Beatrice, a Swiss citizen, was kidnapped in her home in Timbuktu by gunmen," a Timbuktu government official told AFP.
A Malian security source said armed men had gone to her home on Thursday night, "knocked on the door, she opened, and they left with her."
Beatrice Stockly was kidnapped a first time in April 2012 by Islamist fighters but released thanks to mediation efforts by Burkina Faso authorities.
Two foreign hostages seized the previous year in 2011 by members of Al-Qaeda in the Islamic Maghreb (AQIM), a South African and a Swede, are still in captivity.
Jihadist fighters including AQIM members seized control of Mali's vast remote north in March-April 2012 but were chased out the following year by a French-led military intervention.
A regional French counterterrorism force is still conducting operations in the area.
Entire swathes of the north remain beyond the reach of both the Malian army and foreign troops, however.
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