Oil rose for a second session as renewed hostilities between the United States and Iran fed fears that energy flows through the Strait of Hormuz would stay disrupted for a prolonged period on September 1.

Brent traded above $91.74 a barrel after the US struck an island in the Strait of Hormuz and Iran responded with attacks on the UAE and Jordan, according to Newsbase analytical data.

In recent hours, President Donald Trump played down concerns that the conflict was draining American firepower, calling it a "small war"; however, Iran has vowed to continue fighting if the US fails to return to negotiations as part of the Islamabad process.

The number of visible commercial cargo vessels crossing the strait fell to five a day early in the week, shipping data showed, and mediators' efforts to reach a deal to reopen the passage have made no progress.

Crude still moves through the waterway, often on tankers that switch off their transponders to avoid detection, allowing Gulf producers to get some barrels out.

Ships face a persistent threat of attack. One tanker reported being hit by three unidentified projectiles as it moved out of Hormuz, highlighting the risks to regional shipping.

"Traders cut their net crude positions last week as uncertainty persists over the next phase of the conflict with Iran," said Bart Melek, global head of commodity strategy at TD Securities. "We still expect crude prices to rise, as there are no signs of a resumption of normal transit through the Strait of Hormuz in the near term."

Separately, Abu Dhabi National Oil Company (ADNOC) restored full capacity at its Ruwais refinery after damage sustained earlier in the war, according to people familiar with the matter. The plant, one of the world's largest refineries, has run at full capacity for a month, boosting diesel and jet fuel exports.