COPENHAGEN - Europe could face energy shortages next winter after Russia's invasion of Ukraine has deepened the region's energy crisis, the head of the International Energy Agency (IEA), Fatih Birol, warned on Wednesday.

"I am a especially worried about the natural gas markets ... if we have a harsh and long winter we may see very difficult days," said Birol at IEA's annual conference on energy efficiency in Sonderborg, Denmark.

Birol said that while governments and companies were now looking to secure alternative energy supplies, it is equally important for governments to take measures to reduce demand.

If European consumers reduce the temperature in their homes by 2 degrees Celsius, 20 billion cubic meters of natural gas will be saved, equivalent to the volumes coming from Russia to Europe through Nord Stream 1, he said.

(Reporting By Jacob Gronholt-Pedersen, writing by Stine Jacobsen, editing by Anna Ringstrom and Terje Solsvik)