Oil prices jumped above $100 a barrel as energy markets reopened on Monday in Asia after talks between the US and Iran ended without a new deal and Donald Trump said he would blockade Iranian ports.
Global benchmark Brent crude is up by 8.5% at $102.37 (£77.15), while West Texas Intermediate is 9% higher at $105.34.
The failure of negotiations at the weekend has raised concerns that the global energy crisis will deepen.
The price of oil plunged well below $100 last Wednesday after Washington and Tehran agreed to a conditional two-week ceasefire deal that includes the opening of the key Strait of Hormuz trade waterway.
The strait, through which a fifth of the world's energy shipments pass, has become a key flashpoint of the Iran war after Tehran retaliated against the US-Israeli strikes by threatening to attack vessels that try to use it.
