MOSCOW, June 15 (Reuters) - The Russian government has authorised some oil refineries to produce gasoline and diesel fuel at lower environmental specifications for the domestic market, as the country grapples with fuel shortages, the Kommersant newspaper reported on Monday.

Fuel shortages in Russia have been reported by the media and on social media in around a dozen regions, according to data compiled by Reuters. Besides Russian-held Crimea, only two regions in Siberia have officially confirmed the shortages.

Deputy Prime Minister Alexander Novak called last week for fuel market forecasts to guard against difficulties in fuel distribution and meeting domestic demand.

Ukraine has for months targeted Russian refineries, pipelines and fuel depots in an effort to curb Moscow's ability to finance the war on its neighbour, now in its fifth year.

Kommersant reported, citing a source, that the government in autumn relaxed rules for certain refineries allowing them to sell gasoline and diesel fuel on the domestic market that deviates from approved regulations on sulphur content and other indicators.

The measure was in effect until May 1 of this year, but was later extended, Kommersant's source said.