MOSCOW, June 25 (Reuters) - Russia's oil major Gazprom Neft SIBN.MM said on Thursday that talks over the sale of its stake in Serbia's oil firm NIS NIIS.BEL continue and it would require more time to complete, Interfax news agency reported.

The United States imposed sanctions on NIS last year as it targeted the Russian energy sector over Moscow's war in Ukraine and demanded that Russia's Gazprom GAZP.MM and Gazprom Neft divest their NIS shares.

"We are currently holding talks on the share sale. It is a complex deal and will take time to reach an agreement. The process continues," Alexander Dyukov, the head of Gazprom Neft was quoted as saying by Interfax an the company's shareholder meeting.

Last week, the U.S. Treasury's Office of Foreign Assets Control extended a licence to Hungary's energy company MOL MOLB.BU to negotiate the purchase of a majority stake in Serbia's Russian-owned NIS until July 1.