Oil rose a second day as uncertainty over progress in US-Iran talks weighed against signs of strong demand and a resumption of flows through a key pipeline from top exporter Saudi Arabia. West Texas Intermediate advanced above $93 a barrel, while Brent closed near $105.

Iranian officials have privately expressed pessimism about reaching a deal to reopen the Strait of Hormuz before US midterm elections in November. Meanwhile, Saudi Arabia has restored about half the flows through its East-West pipeline, a crucial route bypassing the strait, after drone strikes halted operations.

Flows through the link to the Red Sea have reached at least 3.5 million barrels a day. The fundamental outlook for oil is turning increasingly bullish, with key gauges of supply tightness spiking and fuel prices surging as global refinery capacity remains hobbled.

Crude is headed for a third monthly gain on escalating US-Iran tensions, disruptions to the Saudi bypass route, and potential diesel export curbs by Washington.