BELGRADE, Nov 25 (Reuters) - Operations at Serbia's

Russian-owned NIS oil refinery have halted due to a

lack of crude oil supplies, Belgrade-based NOVA.RS TV reported

on Tuesday, in the latest sign that U.S. sanctions on the

project could threaten fuel supplies across the Balkan country.

Officials at NIS and in the Serbian government declined to

comment.

The U.S. Treasury Department's Office of Foreign Assets Control

(OFAC) placed sanctions on Russia's oil sector in January,

including NIS, which is majority owned by Russia's Gazprom Neft

and Gazprom. The US granted NIS repeated

waivers before the sanctions finally came into effect in

October.

Banks then stopped processing NIS payments and Croatia's

JANAF

JANF.ZA

pipeline halted crude deliveries to the refinery.

Since then, Serbia has been scrambling to secure alternative

fuel supplies for winter.

Serbia's government on Monday said it

has sufficient fuel

reserves to supply the domestic market. But on Tuesday, a

lack of crude meant that the refinery had stopped operating,

NOVA reported, meaning it will not be able to produce more

products like gasoline, diesel and jet fuel.

A refinery source confirmed the news. The refinery does have

fuels in storage, NOVA and the source said.

NIS operational reserves and all other reserves stored with

NIS total 89,825 metric tons of diesel and 53,648 tons of

gasoline, energy minister Dugravka Djedovic Handanovic said on

Sunday. Last week, she said the government had approved the

import of 38,000 metric tons of petrol and 66,000 tons of diesel

for state reserves.

Gazprom Neft holds 44.9% of NIS and Gazprom GAZP.MM 11.3%.

Serbia owns 29.9%, with the rest held by small shareholders.

Washington is seeking complete Russian divestment from NIS

and has given the company's owners three months to find a buyer

of the Russian stake.