Slovenia has become the first European Union member state to bring in fuel rationing as a way of managing disruption to global supply caused by the US-Israeli strikes on Iran.

Energy prices around the world have been in turmoil since the United States and Israel began their attacks, which have caused Iran to shut down the Strait of Hormuz shipping lane — one of the busiest and most important for global fuel supplies.

Slovenia, at the north end of the Adriatic Sea and bordered by Italy, Austria, Hungary and Croatia, has experienced an upsurge in so-called fuel tourism, especially from Austria, where petrol is significantly more expensive, as people drive into the country specifically to take advantage of its regulated, lower prices.

Individual fuel retail companies in some countries, including Hungary, have already imposed purchase limits, but Slovenia, where the general public will be limited to a maximum purchase of 50 liters per day, or 200 liters for commercial and agricultural use, is the first place where rules have been set by the government, although it insists this is a precautionary, rather than a panic measure.

"Let me reassure you that there is enough fuel in Slovenia," said Prime Minister Robert Golob. "The warehouses are full and there will be no fuel shortages."

At the same time, European Energy Commissioner Dan Jorgensen has sent a letter to EU member states, which has been seen by the Euronews website, encouraging them to start refilling gas reserves earlier than usual to avoid pressure on supply, and subsequent rising prices.

"We are still in the early stages of the storage injection season, but it is essential that we start our preparations in time for next winter and in a coordinated manner," said the letter, dated March 20.

He added that the bloc's supply security was "relatively protected" as imports from Qatar, through the Strait, are of limited reliance for EU countries, but Saad Sherida Al-Kaabi, CEO of QatarEnergy, has already warned that his company will not be able to fulfill contractual supply obligations, which will have a ripple effect on global markets, impacting European supplies and prices.

Citing lessons learned following the outbreak of war in Ukraine in 2022, Jorgensen urged countries to take advantage of adjusted refilling targets, which can now be reached over a longer period of time than before.

"This flexibility can help reduce the gas demand at times when the supply is tense and ease the pressure on gas prices in Europe," he said, adding "we have also learned the pitfalls of uncoordinated action".

In the United Kingdom, Chancellor of the Exchequer Rachel Reeves Tuesday has vowed to deliver economic support to British "who need it most" if energy bills rise and the government has begun contingency planning for "every eventuality".