Oil prices rose on Friday, putting them on track for a fourth consecutive monthly gain as traders anticipated a possible escalation in the US-Iran conflict following the US midterm elections. An attack on a tanker in the Strait of Hormuz has further underscored the risks to global supplies posed by the war.

Brent crude futures for December delivery, which expire on Friday, climbed $2.26, or 2%, to $117.14 a barrel as of 1236 GMT. The more actively traded January contract advanced $2.30 to $113.10, The Caspian Post reports, citing Reuters.

US West Texas Intermediate (WTI) crude futures rose $1.94, or 1.9%, to $103.94 a barrel.

For the month, Brent was on course to record a 13% increase, while WTI was heading for a 15% gain.

On Friday, a tanker in the Strait of Hormuz, a key maritime route for crude oil and fuel exports from the Gulf, was struck by explosive devices attached by a small boat, the UK Maritime Trade Operations (UKMTO) said. The identity of those responsible for the attack was not immediately known.

Maritime sources said it was the first known successful attack involving limpet mines - explosives attached to a vessel's hull by a small boat - in the waterway since the US war with Iran began in February.

Meanwhile, Qatari mediators returned to Tehran on Friday as part of coordinated efforts to secure an agreement between Washington and Tehran, an official briefed on the negotiations told Reuters.

On Thursday, Yemen's Iran-backed Houthi militants claimed to have attacked several locations in Saudi Arabia, including the kingdom's largest oil refinery, Ras Tanura, the Rabigh refinery and a production facility in Abqaiq operated by state-owned Saudi Aramco.

A Saudi-led coalition also announced that it had intercepted a Houthi-launched cruise missile heading towards the kingdom's western region.

US President Donald Trump said on Thursday that Vice President JD Vance had contacted Iran to help the country obtain medical supplies. His remarks came after US media reported that Vance had sent a letter to Tehran's top security official in an effort to revive peace negotiations.