Russia may sacrifice a crucial spending rule as the Ukraine war puts the economy under pressure, The Bell reported.

The budget rule dictates that when oil goes above a certain price, excess revenues are saved in a rainy-day fund for use in leaner times, to smooth out volatility.

The Iran conflict has driven prices well above that mark, but Russia’s war spending and Ukraine’s attacks on its oil infrastructure mean Moscow is still cash-strapped.

Sweden’s intelligence chief said Russia would struggle to continue the war, especially if a US-Iran truce brought oil prices down. Russian President Vladimir Putin recently admitted the economy was performing below his expectations, and urged his top economic officials to activate growth.