PARIS, Nov. 3 (Xinhua) -- Europe could face a shortage of as much as 30 billion cubic meters (bcm) of natural gas during the key summer period for refilling its gas storage sites in 2023, the International Energy Agency (IEA) warned on Thursday.

"Europe needs to take immediate action to avoid the risk of natural gas shortage next year," meaning urgent action is required by governments to reduce gas consumption amid the global energy crisis, IEA said.

Gas storage sites in the European Union (EU) are now 95 percent full, IEA noted. However, it warned that the cushion provided by current storage levels, as well as recent lower gas prices and unusually mild temperatures, should not lead to overly optimistic conclusions about the future.

According to the IEA, the process of filling the European Union's gas storage sites this year benefited from key factors that may well not be repeated in 2023.

Europe "could face a challenging supply-demand gap" in the event of a full cession of Russian pipeline gas supplies to the EU, the IEA added.

For the Russian pipeline gas supply, "it is highly unlikely that Russia will deliver another 60 bcm" for 2023.

"Russian deliveries to Europe could halt completely," IEA said.

"With the recent mild weather and lower gas prices, there is a danger of complacency creeping into the conversation around Europe's gas supplies, but we are by no means out of the woods yet," said IEA Executive Director Fatih Birol.