Oil prices jumped 3% on Monday, with Brent surpassing $90 a barrel, as the United States and Iran expanded attacks in the Middle East that have curbed energy shipments in the Strait of Hormuz.
Brent crude futures climbed $2.69, or 3.05%, to $90.79 by 2343 GMT, touching the highest since June 11, extending gains after rising 15.9% last week, its biggest weekly gain since April.
U.S. West Texas Intermediate crude was at $84.68 a barrel, up $2.19, or 2.65%, the loftiest since June 12. Front-month prices gained 15.5% last week, the largest weekly ascent since early March.
The Middle East conflict escalated over the weekend with the U.S. conducting a ninth straight night of attacks against Iran, while U.S. allies Kuwait and Bahrain reported more Iranian strikes.
In recent days both sides have taken aim at shipping traffic, with the U.S. saying it is enforcing a naval blockade on Iranian ports, and Iran saying it targets vessels violating its rules on navigating the Strait of Hormuz, which usually handles one-fifth of global oil trade.
A vessel was on fire northwest of Oman's Kumzar, the United Kingdom Maritime Trade Operations agency said early on Monday.
"The coming days and weeks will provide a clearer picture of the sustainable level of oil exports from the region under renewed dual blockades," Barclays analyst Amarpreet Singh said in a note.
"As things stand, we think oil markets are still too complacent about the potential fallout for inventories, which, unlike at the beginning of the war, are at the tightest of the past five years."
Four vessels made the transit through the Strait of Hormuz on Sunday, down from eight in the previous day, LSEG data showed. At least three oil products tankers and one Very Large Crude Carrier, have entered the strait since Friday to load oil, the data showed.
