European natural gas prices rose amid market jitters about the next phase in the Israel-Hamas war, including the possibility that a wider conflict in the Middle East could disrupt energy supplies.

Benchmark futures settled 1.8% higher, after swinging throughout the day. The contract is up about 30% since Hamas attacked Israel on Oct. 7, igniting the conflict.

President Joe Biden said he’s asked Israel to delay a full ground invasion of Gaza to secure the release of hostages held by Hamas, which is considered a terrorist organization by the US and the European Union. Israeli Prime Minister Benjamin Netanyahu confirmed such action is still being prepared, and the country’s military said it made a brief incursion into northern Gaza.

Israel Latest: Army Briefly Raids Gaza to Prepare ‘Next Stages’

Any escalation that affects the wider region would risk further disrupting gas production and exports from Israel, as well as potentially hindering liquefied natural gas vessels passing through the Strait of Hormuz.

“Escalations in the Middle East are providing bullish sentiment across the gas curve as a heavier risk premium is priced in due to increased supply security concerns,” Inspired Plc said in a note.

The war has coincided with the start of the heating season in the Northern Hemisphere, with Europe still in a vulnerable position as it looks for new sources of gas after Russia cut off most pipeline flows last year.

Storage sites across Europe are almost 99% full, but steady supplies are needed if a prolonged cold snap raises heating demand. Europe heavily depends on LNG flows now, rendering its market reactive to events further away from the continent.

“EU natural gas prices have risen in recent weeks, highlighting that a reliance on LNG imports is not without risk,” Capital Economics said in a note.

TotalEnergies SE, which reported earnings Thursday, said it expects gas markets to remain “tense” in the region this winter despite high inventories. Chief Executive Officer Patrick Pouyanne said LNG buyers in Asia have returned, which could provide competition with Europe for the fuel.

Traders are also weighing supply prospects going into next year, with prices for gas next winter even higher than near-term contracts. For now, a period of colder weather is forecast for late next week, which could test how well the region is prepared for elevated heating demand.

Dutch front-month futures, Europe’s gas benchmark settled at €50.81 a megawatt-hour. The UK contract also closed higher.

--With assistance from Priscila Azevedo Rocha.