Two Russian pilots kidnapped in Sudan's Darfur region in February were freed on Saturday, according to official sources."They have been freed and are on their way to Khartoum (the capital of Sudan)," an official source told Xinhua news agency without giving more details about how they were released.The two Russian pilots, who worked for the UN African Union Mission in Darfur (Unamid), were abducted in February by an unidentified armed group from central Darfur when they were returning from a market to the mission base in Zalenge town.Similar incidents of kidnapping humanitarian workers and Unamid personnel have taken place several times in Darfur region.