MOSCOW, July 6 (Reuters) - Russia's Federal Anti-Monopoly Service (FAS) is preparing an investigation into a suspicious increase in wholesale prices of diesel by domestic producers, a FAS official told Reuters on Thursday.
Domestic sales of diesel have been more profitable than exports since spring, as companies have curtailed sales on the Russian market.
"A situation where the domestic market is more profitable, while there has been no reduction in exports is abnormal. Those are economically illogical actions. Those illogical actions fall under the law of consumer protection requirements," said Dmitry Makhonin, the FAS official.
According to Reuters data, the pricing premium for diesel on the domestic market compared with exports reached up to 8,000 roubles ($133.4) per tonne earlier this year. Russia produces 2.5 times more diesel than it consumes.
Russian oil producers cut diesel supplies domestically by 1.8 percent in January-May, while exports have risen by 5.3 percent.
"We are very concerned and next week we are inviting oil companies for a meeting," Makhonin said. Russian oil producers were not immediately available for comment.
$1 = 59.9660 roubles Reporting by Maxim Nazarov and Olesya Astakhova; writing by Vladimir Soldatkin Editing by Jeremy Gaunt