- The IEA said Russia's estimated oil export revenues fell to $11.6 billion last month, down $2.7 billion from January when volumes were significantly higher.
- "It remains to be seen if there will be sufficient appetite for Russian oil products now that the price cap is in place or if its production will start to fall under the weight of sanctions," the IEA said.
- "Revenues are already dwindling," the energy agency added.
The International Energy Agency on Wednesday said Russia's oil export revenues fell sharply in February, prompted by bans and price caps designed to curtail President Vladimir Putin's ability to finance the war in Ukraine.
The IEA said Russia's estimated oil export revenues fell to $11.6 billion last month, down $2.7 billion from January when volumes were significantly higher.
"It remains to be seen if there will be sufficient appetite for Russian oil products now that the price cap is in place or if its production will start to fall under the weight of sanctions. Revenues are already dwindling," the group said in its latest oil market report.
The energy agency said, citing the Russian finance ministry, that Moscow's fiscal receipts from oil sales were just 45% of the level from a year earlier.
The latest figures come shortly after the IEA said in mid-February that the West's oil war against Russia appeared to be having the "intended effect" despite surprisingly resilient production and exports in recent months.
Ukrainian officials and campaigners have previously called for Western policymakers to ramp up the financial pressure on Russia by targeting its oil revenues in order to help Kyiv prevail.
The European Union's embargo on Russian oil products came into effect on Feb. 5, building on the $60 oil price cap implemented by the Group of Seven major economies on Dec. 5. The latter measure also coincided with a move by the EU and U.K. to impose a ban on the seaborne import of Russian crude oil.
Asked on Tuesday whether he was concerned last year that the Russian economy might have collapsed due to international sanctions, Putin said he had been worried but that Russia's "economic sovereignty" now was a major result. The foundations of Russia's economic stability were "stronger than anyone thought," he added.
Putin said Russia's financial system had got stronger and that Western companies that left Russia last year thought the economy would collapse "but it didn't."
— CNBC's Holly Ellyatt contributed to this report.