ZURICH (Reuters) - Switzerland on Sunday called for the quick release of a Swiss woman reported abducted in Sudan s troubled Darfur region where rebels have been fighting the government for more than a decade.  The Foreign Ministry is aware of the case of a Swiss woman kidnapped in Darfur,  a ministry spokesman said by email.   Local representation is in contact with Sudanese authorities. Efforts to clarify the situation are in progress. Switzerland is calling for a rapid and unconditional release of the abducted person.  The ministry did not give details about when the woman had been abducted or other details about her. Swiss newspapers reported the woman was an aid worker. Sudan will extend a unilateral ceasefire with rebels until the end of December, state news agency SUNA reported on Sunday, just days after the United States lifted 20-year-old sanctions tied to progress on resolving ongoing conflicts. The conflict in Darfur began in 2003 when mainly non-Arab tribes took up arms against Sudan s Arab-led government. 