LISBON - Portuguese oil and gas company Galp said on Thursday it would be a "very hard task" for the European Union to significantly slash its imports of Russian natural gas this year while increasing gas stocks at the same time.

Russia's invasion of Ukraine has pushed energy prices to record highs and prompted the EU to pledge to cut Russian gas use by two-thirds this year by increasing imports from other countries and expanding renewable energy.

EU also said it wanted to increase gas stocks to 80% by the beginning of November.

"It is very hard to see how they (EU) can both rebuild the stocks and reduce the gas taken from Russia," CEO Andy Brown told a news conference.

"At the moment, Russian gas is still flowing into Europe... if we (EU) want to rebuild stocks we will have to keep that flow going," he said, adding that the EU could become less reliant on Russian gas in the future but it would have to compete with Asian countries, which would keep gas prices high for some time.

Russia supplies around 40% of the bloc's natural gas consumption through pipelines and the EU also gets a third of its oil imports from the country.

EU leaders backed the recommendation two weeks ago that European countries jointly buy gas to shore up supply, but fell short of imposing a cap on energy prices. Brown said the EU should, instead, focus its efforts on accelerating LNG projects and diversifying its sources of gas supply, for example, "providing security to Nigeria, which is the main supplier of LNG to Portugal." "Gas is an internationally traded commodity. There is no such thing as a 'cap' on international prices," he said. However, decoupling the electricity market from rising gas prices used in power electric plants is a "valuable" idea as proposed by Iberian countries.

(Reporting by Sergio Goncalves and Catarina Demony, editing by Andrei Khalip and Bernadette Baum)