Serbia has secured a three-month reprieve on the Russian-owned oil company NIS , which is under U.S. sanctions that threaten fuel supplies at the country ahead of winter, a government official said on Saturday. Serbia said this week that Russia's Gazprom Neft and Gazprom - which together hold a controlling stake of 56% in its sole oil refinr NIS had sent a request to the U.S. Treasury's Office of Foreign Assets Control (OFAC), stating readiness to cede control of the company to a third party. OFAC initially placed sanctions on Russia's oil sector, including Gazprom, in January, but for NIS they were postponed several times and finally came into effect on October 8.