Switzerland's foreign ministry said Monday it is working toward the release of a Swiss woman kidnapped in the northern Mali city of Timbuktu, as rebels in the area said they would have protected her had they known she was there.

The woman, who was working as a missionary, was taken from her home Sunday afternoon, according to Kader Kalil, director of Radio Bouctou.

Foreign ministry spokesman Adrian Sollberger said Monday that Swiss officials are working with local authorities and others. He said the foreign ministry has advised against travel to Mali since 2009 because of the risk of kidnapping.

Almost all Westerners have left the north of Mali since Tuareg fighters and an Islamist group with links to al-Qaida's North Africa branch took control of the area weeks ago.

The developments came after Mali's longtime president was ousted in a coup last month.

A spokesman for the group seeking independence, the National Movement for the Liberation of the Azawad, said the group had been unaware of the presence of the Swiss woman in the town.

"If we had known that she was there we would have done everything in our power to protect her," Moussa Ag Assarid said. "We already managed to help evacuate a number of Westerns from Timbuktu since we arrived there.

"What was she doing there anyway with the Islamist group Ansar Dine and AQIM also operating in the area?" he said, using the acronym for al-Qaida in the Islamic Maghreb. "We're doing our best, but we can't control every vehicle that comes in and out of Timbuktu. We need time to organize our troops."

The al-Qaida militants have been responsible for dozens of kidnappings of Westerners in the Sahel region over the last five years.