Brent crude futures were up $4.57, or 6.16%, to $78.73 a barrel at 0948 GMT, while US West Texas Intermediate crude climbed $4.23, or 6.01%, to $74.67 a barrel.

The benchmarks ​are at their highest levels since June 22.

Both rose about 3% on Tuesday after the US revoked the general ​licence authorising the sale of Iranian crude.

Trump said on Wednesday that the memorandum of understanding signed with ⁠Iran to end the conflict was “over”, adding he didn’t want to engage with Tehran.

The agreement, brokered by Pakistan last month ​to provide a 60-day window for negotiations, came under strain after the US launched fresh strikes on Iran.

“The market is again ​being forced to price the risk that renewed attacks on shipping, or a broader breakdown in US-Iran relations, could slow the normalisation of flows through the Strait of Hormuz,” Saxo Bank analyst Ole Hansen said.

The US air strikes were in response to Iranian attacks on three commercial vessels that were ​transiting the Strait of Hormuz, US Central Command said on Tuesday.

Iran’s Revolutionary Guards then said they targeted US military ​sites in Bahrain and Kuwait early on Wednesday.

The attacks renewed concerns about tanker traffic through the Strait of Hormuz, which carried about ‌one-fifth of ⁠global energy supply before the war began in late February.

Supply fears resurface

“Trump’s assertion that the MOU is over raises the prospect of a re-closing of the Strait as an escalatory cycle begins again,” Sauk Kavoniv, head of research at MST Marquee, said.

At least four oil and gas tankers have turned back from attempting to transit the strait, ship-tracking data showed, as renewed ​attacks on vessels heightened safety concerns.

“(The) ​underlying supply challenge has ⁠not disappeared, but the latest escalation has interrupted it,” Hansen added.

After the US and Iran signed their truce last month, oil prices tumbled to pre-war levels, and traders amassed large short positions in ​oil futures, betting prices would fall further.

Since the start of the conflict, nations have drawn ​down their inventories ⁠to make up for the supply shortfall.

“In my view, a price closer to $80 a barrel is more consistent with current market fundamentals than $70,” said Bjarne Schieldrop, chief commodities analyst at SEB.

Meanwhile, China has lifted refined fuel export restrictions for the rest of July and ⁠allowed a ​private refiner to resume shipments after a four-month halt, trade sources said ​on Wednesday, as the world’s biggest refiner returns towards normal after disruptions from the Iran war.