Oil prices rose on Monday on a re-escalation of hostilities in the Middle East war after Iran closed the Strait of Hormuz at the weekend, just a day after reopening it, citing the United States' blockade of its ports, and a second round of talks in Pakistan appeared to be uncertain.
However, lingering hopes for a deal to end the seven-week crisis continued to support Asian equities, even as Tehran said it was not currently planning to attend peace talks.
Crude plunged on Friday while U.S. stocks rallied after Iran said it would again allow ships to pass through the waterway, through which a fifth of global oil and liquified natural gas (LNG) usually passes, citing the cease-fire between Israel and Lebanon.
U.S. President Donald Trump said that "we're very close to having a deal," adding that there were "no sticking points at all" left with Tehran, though Iran quickly pushed back, saying its stockpile of enriched uranium would not be transferred "anywhere."
U.S. benchmark West Texas Intermediate (WTI) dived more than 11% and Brent shed 9%.
But both contracts jumped sharply on Monday, days before the end of a two-week ceasefire, owing to the ongoing U.S. blockade and after an American destroyer fired on and seized an Iranian ship that tried to evade it. Tehran warned it would retaliate.
The blockade of Iranian ports has been a significant sticking point in negotiations between the two countries, and state broadcaster IRIB cited Iranian sources as saying "there are currently no plans to participate in the next round of Iran-U.S. talks" in Pakistan.
The Fars and Tasnim news agencies had earlier cited anonymous sources as saying "the overall atmosphere cannot be assessed as very positive," adding that lifting the U.S. blockade was a precondition for negotiations.
WTI jumped more than 7% at one point, while Brent piled on more than 6%.
There has so far been only a single, 21-hour negotiating session held in Islamabad on April 11 that ended inconclusively, though groundwork for fresh talks continued afterwards.
"We're offering a very fair and reasonable DEAL, and I hope they take it," Trump said in a social media post Sunday, while also renewing his threats against Iran's infrastructure if a deal is not made.
But Iran's Revolutionary Guards warned that any attempt to pass through the strait without permission "will be considered cooperation with the enemy, and the offending vessel will be targeted."
Foreign Ministry spokesperson Esmaeil Baqaei said the blockade was "a violation" of the cease-fire.
Still, Asian equities rose, tracking another record close for the S&P 500 and Nasdaq in New York.
Tokyo, Hong Kong, Seoul, Shanghai, Sydney, Singapore, Mumbai, Wellington and Manila were all up, helped by a resumption of a tech rally that characterized world markets before the war started on February 28.
But London, Paris and Frankfurt dropped.
The dollar, which has been a key safe haven during the crisis and fell sharply on Friday, advanced against its main peers.
Chris Weston at Pepperstone said traders were assessing "whether the cease-fire can be salvaged through this week's diplomatic talks, with recalibration on the probability of military escalation."
"Trump's weekend social media posts raised the prospect of military re-escalation, though given the bar for this response is now set higher, some viewed this as a pure hawkish negotiating tactic ahead of this week's diplomatic talks," he added.
"Market participants understand that the path to a formal agreement (is) unlikely to be linear and remains vulnerable to sudden changes, so market players won't be wholly surprised by a sentiment shift.
"However, without a comprehensive agreement on Iran's nuclear program, the cease-fire remained fragile."