Global oil prices have risen back above $110 (£83.38) a barrel after US President Donald Trump threatened to destroy critical infrastructure in Iran unless it allows ships to cross the Strait of Hormuz.
On Monday morning in Asia, Brent crude rose by 1.6% to $110.85, while US-traded oil was up by 0.8% at $112.40.
In an expletive-laden social media post on Sunday, Trump said the US would attack power plants and bridges unless the crucial waterway is open by Tuesday.
Oil and gas shipments from the Middle East have been severely disrupted as Tehran threatens to attack vessels that try to use the strait in retaliation for US and Israeli airstrikes since 28 February.
Disruption to shipping in the narrow waterway, through which a fifth of the world's energy shipments usually passes, has pushed up the price of energy around the world and raised concerns about higher inflation globally.
Oil prices rose above $100 a barrel last week after Trump intensified threats against Iran, warning that US airstrikes over the next few weeks would send the country "back to the Stone Ages".
Iranian attacks on oil facilities in the Gulf continued over the weekend.
Tehran claimed responsibility on Sunday for a wave of strikes on petrochemical plants in Kuwait, Bahrain and the United Arab Emirates.
On Monday, the Iranian Revolutionary Guard Corps (IRGC) warned that its attacks against US economic interests would be intensified if civilian infrastructure in its country continues to be targeted.
On Sunday, Opec+ - which includes major oil‑producing members of the Organization of the Petroleum Exporting Countries like Saudi Arabia and Russia - agreed a small increase to crude output in May.
But the 206,000 barrels a day production hike will largely exist on paper only as several of the group's key members are unable to increase output due to the conflict.
Trump has postponed several deadlines for Iran to remove its threats against ships using the strait but repeated his demands in the strongly-worded Truth Social post.
The paragraph below contains very strong language.
Trump wrote on Sunday: "Tuesday will be Power Plant Day, and Bridge Day, all wrapped up in one, in Iran. There will be nothing like it!!! Open the Fuckin' Strait, you crazy bastards, or you'll be living in Hell - JUST WATCH! Praise be to Allah. President DONALD J. TRUMP".
A few hours later, in a post on the same platform, he said: "Tuesday, 8:00 P.M. Eastern Time!"
Trump told Fox News there was a "good chance" an agreement would be reached on Monday, but said he was considering "blowing everything up and taking over the oil" if a deal was not reached soon.
Senior Iranian military officer Gen Ali Abdollahi Aliabadi dismissed an earlier Trump deadline, calling it "helpless, nervous, unbalanced and stupid", adding that "the gates of hell will open" for the US leader.
BBC