KHARTOUM (Reuters) - 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. Fighting between the army and rebels in Kordofan and Blue Nile regions broke out in 2011, when South Sudan declared independence. Conflict in Darfur began in 2003 when mainly non-Arab tribes took up arms against Sudan s Arab-led government. Making progress on resolving these conflicts was one of several demands made by the United States for it to lift a trade embargo, unfreeze assets and remove financial restrictions that have isolated the country for years. The ceasefire was set to expire at the end of October. 