Ukraine President Volodymyr Zelensky has criticised a price cap set by his Western allies on Russian oil exports, calling it "weak".
The cap, approved on Friday, is aimed at stopping countries paying more than $60 (£48) for a barrel of seaborne Russian crude oil.
Russia says it will not accept a cap on prices for its oil exports.
The measure - due to come into force on Monday - intensifies Western pressure on Russia over the invasion.
But Mr Zelensky called the price cap "a weak position" and not "serious" enough to damage to the Russian economy.
"Russia has already caused huge losses to all countries of the world by deliberately destabilising the energy market," he said in his nightly address.
It is "only a matter of time when stronger tools will have to be used", he added.
The price cap was put forward in September by the G7 group of industrialised nations (the US, Canada, the UK, France, Germany, Italy, Japan and the EU) in a bid to hit Moscow's ability to finance the war in Ukraine.
In a joint statement, the G7, the European Union and Australia said the decision was taken to "prevent Russia from profiting from its war of aggression against Ukraine".
On Saturday, Kremlin spokesman Dmitry Peskov said that Moscow had prepared for the move but would "not accept" the cap.
Though the measures will most certainly be felt by Russia, the blow will be partially softened by its move to sell its oil to other markets such as India and China - which are currently the largest single buyers of Russian crude oil.
https://www.bbc.co.uk/news/world-europe-63848257