US President Donald Trump has blamed Ukraine's attacks on Russian oil refineries for the global reduction in diesel exports and the spike in prices around the world, saying President Volodymyr Zelensky "wants to make problems for the world".
"He'd better damn well stop," Trump said, before suggesting Ukraine should "get a new leader who can make a deal".
But others have pointed the finger of blame at the US-Israel war with Iran for cutting exports of the refined fuel from the Gulf region.
After Trump announced a controversial deal to import diesel from Russia - promising "lower prices for Americans" - BBC Verify has looked at what has been affecting supplies of the fuel in recent months and years.
The figures suggest that while both the Ukraine and Iran conflicts have significantly reduced global diesel exports - the fall in supplies from the Gulf states due to the war with Iran has been greater.
While the rising cost of diesel directly hits drivers, there's a wider concern because of its use in the lorries, vans and ships that form the backbone of global supply chains. Any increase in transport costs could be fed through to consumers in the form of higher prices.
Average US retail diesel prices on 5 October were $6.20 (£4.69) per gallon, just shy of the record of $6.50 per gallon seen on 21 September, according to the latest figures from the US Energy Information Administration.
Before the war with Iran a gallon of diesel in the US cost around $3.50.
Similarly, average UK diesel prices are currently touching record highs, with data from the Department for Energy Security and Net Zero showing that on 5 October a litre cost 199p.
As well as being a major exporter of crude oil, the Middle East is also a significant global hub for the production of diesel.
In 2025 the Gulf states - Saudi Arabia, UAE, Kuwait, Bahrain and Oman - were exporting around 1.4 million barrels of diesel per day.
In September 2026 that had fallen to around 670,000 barrels per day.
This sharp decline has been driven by the impact of the US-Iran war on the flow of exports of refined diesel from the Gulf states through the Strait of Hormuz.
Traffic flows in the waterway have been badly disrupted by Iranian strikes on tankers and the US blockade of Iran's ports.
While estimates from ship-tracking firms suggest the flow of crude oil through the waterway returned close to pre-war levels last month - due, in part, to the US navy helping to protect shipping - the flow of refined diesel from the Middle East has remained far below pre-war levels.
"The US-Iran conflict delivered a major shock to global energy markets in 2026, but the ongoing Russia-Ukraine conflict is now amplifying this pressure by taking Russian refineries offline," Paul de Leeuw, director of the Energy Transition Institute at Robert Gordon University, told BBC Verify.
His comments were echoed by Rory Johnson, an oil analyst at Commodity Context, who said Ukraine's attacks are "bringing the pain of the war to the Russian homeland and largely knocking the world's second-largest diesel exporter out of the market".
