Brent crude rose above $123 a barrel on Tuesday, the highest it has been for two months.
Prices for oil and gas have soared in recent months, fuelled by the lifting of lockdowns and the Ukraine war.
Rising energy costs are putting pressure on consumers, making it more expensive to heat homes and drive.
Petrol hit a new record of 173.02p a litre on Monday, according to the AA.
At the same time, the average price of diesel in the UK rose to 182.58p a litre, it said.
Filling a typical 55-litre tank of a diesel now costs more than £100.
The war in Ukraine has pushed countries in the West to shun Russian energy supplies.
Russia currently supplies 27% of the EU's imported oil and 40% of its gas. The EU pays Russia around €400bn (£341bn) a year in return.
The ban agreed by EU leaders will see an immediate ban on Russian oil being transported into the bloc by sea. Two-thirds of Russian oil arrives by sea.
However, the deal, which followed weeks of wrangling, includes a temporary exemption for pipeline oil following opposition from Hungary.
Pledges by Poland and Germany to stop importing pipeline oil by the end of this year will raise coverage of the ban to 90% of Russian imports.
Brent crude, the global benchmark for oil prices, has risen more than 70% over the past year.
Oil prices climbed again on news of the EU embargo, with Brent crude reaching its highest level since March.
Russ Mould, investment director at AJ Bell, said confirmation that the EU will cut its purchases of Russian oil by the end of 2022 is pushing up prices because European countries now need to find alternative sources of supply.
"It is not feasible to replace that amount of energy with other fuel sources, such as wind, solar, biomass or nuclear, in such a short space of time, so the EU needs to find oil and gas from somewhere," Mr Mould said.
"This will not be easy because existing global output may well be on contract already, so competition for what is not on contract will now be hotter."
Sophie Lund-Yates, lead equity analyst at Hargreaves Lansdown, said the upwards trajectory of oil prices may continue until Western countries outline clearly how supply is going to be sourced.
"It's possible this could get tougher before it gets better," she said.
"We know that rising energy costs are a particular challenge for households which already have severe pressure on their incomes, but smaller businesses shouldn't be left out of the equation either - this is a tough time to be heating offices, and at a time when it's meant to be about rebuilding resilience after the pandemic."
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.
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.
EU members spent hours struggling to resolve their differences over the ban on Russian oil imports.
Hungary, which imports 65% of its oil from Russia through pipelines, resisted the new round of sanctions.
The cost of living crisis being felt across Europe has not helped either. Sky-rocketing energy prices - among other things - have curtailed some EU countries' appetite for sanctions which could also hurt their own economies.