BELGRADE, Dec 24 (Reuters) - The U.S. has granted Serbian oil refiner NIS until March 24 to negotiate the sale of its ‌Russian owner's stake, Serbia's state-owned RTS TV ​reported on Wednesday.

However, RTS said NIS ‍had not obtained an operating ⁠licence ⁠that would allow it to buy and process ‌crude oil.

The U.S. ​Treasury Department's Office of Foreign Assets Control imposed sanctions on ⁠NIS in October, ‍as ​part of broader measures against Russia's energy sector, after granting a series ‍of waivers since January.

The sanctions have halted crude supplies via Croatia's JANAF pipeline, shutting down production at the Pancevo refinery.

Russia's Gazprom has ​an ‍11.3% stake in NIS, while its sanctioned oil unit Gazprom ​Neft holds 44.9%. The Serbian government has 29.9%, with the remainder held by small shareholders and employees.

Serbian President Aleksandar Vucic said on Tuesday that Gazprom was ​in talks with Hungary's MOL over a possible sale of its majority stake in NIS.