Europe's efforts to diversify suppliers will not be enough to get it through winter without Russian gas, the head of the International Energy Agency (IEA) warned Monday, urging immediate efforts to cut demand. 

The comments by the IEA's director Fatih Birol came as European Commission President Ursula von der Leyen signed an energy deal in Baku, under which deliveries of Azerbaijani gas will double over the next few years.  

But Birol said in an article published by the IEA, "It is categorically not enough to just rely on gas from non-Russian sources – these supplies are simply not available in the volumes required to substitute for missing deliveries from Russia.  

"This will be the case even if gas supplies from Norway and Azerbaijan flow at maximum capacity, if deliveries from North Africa stay close to last year's levels, if domestic gas production in Europe continues to follow recent trends, and if inflows of liquefied natural gas (LNG) increase at a similar record rate as they did in the first half of this year," he added. 

Europe is also waiting to see this week if Russia resumes gas shipments via Gazprom's key Nord Stream 1 pipeline, on which 10 days of scheduled maintenance will soon be completed. 

It has been seeking to import more LNG to replace some Russian gas, but it has a limited number of terminals to offload it from tankers and supplies are also limited. 

While the EU has not put Russian natural gas under sanctions over Moscow's "special military operation" in Ukraine, it has sought to cut imports so as to reduce its dependence on Moscow.