The fire at one of the country's biggest oilfields in the western Siberian region of Khanty-Mansiyisk broke out in a furnace used to evaporate water from crude oil in early January.

The field was developed by Rosneft unit RN-Yuganskneftegaz. RN-Yuganskneftegaz produced more than 70 million tonnes of oil in 2018. Rosneft accounts for around 40 percent of Russia's total oil production.

The source said the combined rate of oil flows at the unit's wells stands at 23,000 tonnes per day, or 12 percent of an average daily production by Yuganskneftegaz, Rosneft's largest oil producing unit.

It was not known how long production was halted or the current status of the wells. A Rosneft spokesman said work at the field is ongoing in a "routine mode", declining further comments on the stoppage.

Another industry source told Reuters that overall Russian oil production edged up to 11.39 million barrels per day (bpd) on average between Jan. 1 and Jan. 22 compared to the period between Jan. 1 and Jan. 10.

(Reporting by Oksana Kobzeva, writing by Vladimir Soldatkin; Editing by Elaine Hardcastle)