Russia’s oil export earnings fell to $17.7 billion in August, the lowest level since March, as lower oil prices outweighed a rise in exports, according to International Monetary Fund for Energy (AIE) data compiled by Bloomberg.

That’s down $1.2 billion from the previous month, even as daily exports of crude oil and petroleum products from Russia rose by 220,000 barrels to 7.6 million barrels.

“Revenues from Russian oil could suffer further when EU sanctions on Russian oil imports take effect in December,” the IEA said in its monthly report on Wednesday.

Russia’s federal budget, which derives more than a third of its revenue from oil and gas, received 671.9 billion rubles ($11.1 billion) in August, the lowest petrodollar inflow in 14 months, according to Bloomberg calculations.

The G7 is trying to find ways to limit Russia’s income from oil exports, according to Reuters. Several different countries have banned imports of Russian crude oil and fuel, but Moscow has so far managed to maintain its revenues by increasing crude oil sales to Asia, particularly China and India.

US Treasury Secretary Janet Yellen and other Biden administration officials have visited oil-consuming countries to promote a mechanism aimed at reducing Russia’s income from oil exports, the source of funding for its military machine, without reducing Russia’s supplies to global markets.

In June, the European Union introduced a package of sanctions that ban the import of crude oil by sea from December 5 and ban the import of petroleum products from February 5, 2023 (with some exceptions).

Importantly, the sanctions also prohibit EU companies from providing shipping insurance, brokerage services or financing Russian oil exports to third countries.