China’s regulator has asked its biggest state-owned natural gas suppliers to fill up storage facilities heading into the peak winter heating season, underscoring risks from rising geopolitical tensions to the nation’s energy security.

The National Energy Administration said China’s demand for gas is increasing and, while the domestic market is “generally in balance,” major providers need to make every effort to keep houses warm in the winter and cope with any complications to international supplies, it said in a statement on Tuesday.

Asian spot prices for liquefied natural gas have rallied about 25% since the Oct. 7 attack by Hamas on Israel intensified fears about global energy security, as Europe prepares for its second winter without much of the pipeline gas from Russia that it once took for granted.

Top producers PetroChina Co., Sinopec and Cnooc Ltd., along with the state-owned pipeline operator PipeChina, were told to increase output, stabilize prices and keep tanks full. The firms will also have to guarantee contracted supply volumes to key users and stick to market-based pricing, the NEA said.

Beijing has relaxed price caps on gas sales to better reflect costs as demand improves after the pandemic and industrial activity expands. Consumption increased 7.4% over the first eight months of the year, while LNG imports rose 12%.

PetroChina, the biggest producer, said it has raised gas injections to an all-time high at underground sites supplying northern China, according to a statement. China’s heating season begins for some northern cities on Friday.