Diplomatic tensions between Russia and Opec are set to deepen this week as oil cartel members resume talks in Vienna.
The factions are likely to agree on an extension of the supply cap pact beyond its March 2018 expiry.
However, calls for the freeze to last until the end of next year have already had a frosty reception from Russian oil bosses, whose patience with the constraints is wearing thin.
Moscow helped broker the unprecedented co-operation deal which has helped drive prices back above US$60 a barrel, but its sluggish economy has increased the appetite to boost oil flows to take advantage of higher oil prices.
Oil bosses are also concerned that prices north of Russia's US$55 a barrel market sweet spot will lure US shale drillers back to the market, said Chris Weafer of Macro Advisory.