Oil prices rose above $100 a barrel on Wednesday following further blows in the US-Iran conflict and ongoing Houthi attacks in Saudi Arabia.
The US retaliated against five Iranian tankers after Tehran struck one of its warships.
Brent crude, the global price benchmark, has not been this expensive since late July, when the ceasefire between Iran and the United States collapsed.
Yemen’s Iran-backed Houthi movement also attacked oil facilities in Saudi Arabia and attacked tankers in the Red Sea on Tuesday.
Brent crude did fall to $99.90 a barrel, but any new flare-ups in the Middle East could send the price higher again.
US strikes on five Iranian tankers damaged four in the Gulf of Oman associated with the Islamic Revolutionary Guard Corps (IRGC) and another near Kharg Island.
Tehran responded by firing missiles at a US base in Jordan (most of which were shot down) and said it had attacked two US ships and eight oil tankers in the Strait of Hormuz.
Oil prices have fluctuated wildly during the war, which began on February 28 this year.
Before the conflict, Brent crude was trading at around $70 (£52) a barrel.
But the war led to the virtual closure of the Strait of Hormuz, through which 20% of the world’s oil and liquefied natural gas (LNG) is transported.
The rise in prices has caused a huge jump in gasoline prices around the world for motorists at gas stations.
Tit-for-tat attacks between Iran and the US intensified last week, more than six months after the US and Israel launched attacks on Iran on February 28.
Jordan said it shot down 18 of 20 Iranian missiles, with two of them falling in deserted areas, a Jordanian Armed Forces spokesman said.
After warning of further retaliatory strikes, Iran’s Revolutionary Guards said on Wednesday that they had attacked two American ships, eight oil tankers and 10 “non-compliant vessels” attempting to pass through the Strait of Hormuz, state media reported.
The latest round of escalation came after Iran aimed ballistic missiles at a US warship, which Centcom said were evaded. He added that no American soldiers were injured during the attacks.
The US responded by saying the five Iranian oil tankers it attacked were “part of a multi-billion dollar shadow network that funds the IRGC and its regional proxies.”
One of the ships it struck, the M/T Riesco, sank in the Gulf of Oman, Centcom later reported, posting video of the damaged vessel on X.
Khark Island, where one Iranian tanker was attacked in the latest series of US strikes, is home to Iran’s main oil export terminal.
About 90% of the country’s crude oil passes through the Gulf island and is transported by pipeline from the mainland.
Pressure on oil prices is compounded by wider regional instability.
Also on Tuesday, Yemen’s Iran-backed Houthi movement attacked energy facilities and civilian infrastructure in Saudi Arabia, wounding 73 people, according to Saudi authorities.
According to Saudi Arabia’s Ministry of Defense and Energy, the drone and missile attack caused fires at oil sites and facilities, leading to a temporary halt in operations.