Brent crude, the most important benchmark for global prices, rose as much as 3 percent on Sunday to top $106 a barrel, before easing somewhat early on Monday.
The latest rise came after US President Donald Trump called on other countries to help Washington reopen the Strait, which usually transports about one-fifth of the global oil supply.
Trump’s proposal has received a muted response so far, with none of the countries he appealed to by name including China, Japan, France and the UK publicly committing to deploying their navy to the critical waterway.
In an interview with The Financial Times on Sunday, Trump said that NATO would face a “very bad” future if his proposal received “no response, or if it’s a negative response”.
Iran has brought shipping in the strait to a standstill in retaliation for the US and Israel’s strikes on the country, resulting in what the International Energy Agency has called the largest disruption to global energy supplies in history.
Global oil prices have risen more than 40 percent since the start of the war, pushing up fuel prices and heightening fears of a slowdown in the global economy.
According to the United Kingdom Maritime Trade Operations (UKMTO) centre, no more than five ships have passed through the strait each day since the start of the war, compared with a historical average of 138 daily transits.
