EU leaders say they will block most Russian oil imports by the end of 2022 to punish Moscow for invading Ukraine.
The EU-wide ban will affect oil that arrives by sea – around two-thirds of imports – but not pipeline oil, following opposition from Hungary.
Poland and Germany have also pledged to end pipeline imports, meaning a total of 90% of Russian oil will be blocked.
European Council chief Charles Michel said the deal cut off a huge source of financing for the Russian war machine.
It is part of a sixth package of sanctions approved at a summit in Brussels, which all 27 member states have had to agree on.
Russia currently supplies 27% of the EU’s imported oil and 40% of its gas. The EU pays Russia around €400bn ($430bn, £341bn) a year in return.
So far, no sanctions on Russian gas exports to the EU have been put in place, although plans to open a new gas pipeline from Russia to Germany have been frozen.
The UK – which gets 8% of its oil needs from Russia – has pledged to phase out Russian oil by the end of the year.
Oil prices climbed on news of the EU embargo, with Brent crude rising above $123 a barrel, its highest level since March.
BBC