Oil prices leapt to nearly $110 a barrel after Iranian media reported an airstrike hitting a facility on the world's largest natural gas field.
The Brent crude oil benchmark hit $109.91 a barrel just after 14:30 GMT, more than 5% higher than Tuesday's prices. It remains above $108.
The surge followed a report from Tasnim, a news agency affiliated with the Islamic Revolutionary Guard Corps (IRGC), that Iran's petrochemical complex on the South Pars gas field had been hit.
The benchmark UK gas price also jumped by 6% to 143.53p a therm before falling back below the 140p mark.
While the price of both oil and gas spiked, they remained below highs seen earlier in the conflict. Oil reached $116.78 a barrel on 9 March, while UK gas reached 162.55p a therm on 3 March.
Iran's oil ministry said a fire at the petrochemical complex was under control on Wednesday afternoon, Tasnim reported, but the extent of the damage to the facility remained unclear.
Iran's military warned it would take decisive action in response to the strike on its energy infrastructure. As previously warned, if the fuel, energy, gas, and economic infrastructures of our country are attacked by the American-Zionist enemy, in addition to a powerful counterattack against the enemy, we will severely strike the origin of that aggression as well, the military said in a statement published by Tasnim.
Iran has also suspended the flow of gas to Iraq in response to the attack to shore up domestic supplies, a senior Iraqi official told Reuters. The vast majority of Iran's gas supply - 94% - is used domestically, according to data from the Gas Exporting Countries Forum.
However, Qatar also operates facilities on the gas field, which it calls North Dome. Qatar, which produces a fifth of the world's liquefied natural gas, had halted production earlier in March in response to the conflict. Qatar's foreign ministry spokesman Majed Al Ansari said strikes against energy infrastructure constitutes a threat to global energy security.
