A trio of European energy CEOs has sounded a warning over energy supplies, amid the ongoing conflict in Iran and restricted access through the strategically vital Strait of Hormuz.

Amid volatile trade, crude prices have surged around 40% in recent weeks, at one point approaching $120 a barrel as investors raised concerns over a potential lack of supply.

Those concerns have been felt particularly in Asian countries so far, with the Philippines announcing an energy emergency, while South Korea says it is preparing for “worst-case scenarios.”

Japan’s Prime Minister Sanae Takaichi has asked the International Energy Agency to consider an additional release from global crude stockpiles, with the global energy watchdog having already coordinated the release of 400 million barrels of oil amongst member countries.

Japan will release national stockpiles on Thursday, with Takaichi confirming Tokyo will access the IEA stockpiles toward the end of the month.

But now there are fears the supply concerns will move westward.

“South Asia was first to get that brunt. That’s moved to Southeast Asia, Northeast Asia and then more so into Europe as we get into April,” Shell CEO Wael Sawan said at CERAWeek in Houston, Texas.

Sawan warned governments not to take actions that could magnify the impact of supply disruptions, adding that you cannot have “national security without energy security.”

Governments across Europe have already started introducing measures to shield households from rising energy costs.

Slovenia became the first country in Europe to introduce fuel rationing, Spain approved a 5-billion-euro ($5.8 billion) aid package, which included tax reductions on electricity and gas, as well as subsidies for transport operators, farmers and for the purchase of fertilizers.

European Union leaders have also discussed temporary measures to mitigate the impact of rising energy prices.

TotalEnergies CEO Patrick Pouyanné said the current oil products market is “dislocated,” telling CNBC that this is why “you see the impact in many countries, in Europe, on the gasoline price, diesel price, people being very unhappy.”

Pouyanné also raised concerns over Europe’s attempts to refill its gas storage over the summer months, warning that this will come at the same time as strong demand from Asia. He also forecast liquefied natural gas (LNG) prices of 40 euros per megawatt-hour if the conflict in the Middle East continues through to the summer.

In the U.K., Finance Minister Rachel Reeves said contingency planning was taking place to protect households and businesses from rising energy costs — but ruled out a universal bailout, saying the government must be “agile” in its response.

Enquest, a North Sea-focused oil producer, also warned of a “significant” impact in the medium-to-longer term, with 2 to 3 million barrels per day removed from the market amid lost production, telling CNBC that excess capacity is gone “for years.”

Speaking on “Squawk Box Europe” on Wednesday, CEO Amjad Bseisu also expressed his concern over what comes next for the Strait of Hormuz, saying “the future is not clear.”