Oil crosses $100 again as Middle East attacks fuel supply fearsHormuz conflict intensifiesChina could determine how far prices goOPEC cuts demand forecastOil prices extended their gains on Friday, with both major benchmarks on track to finish the week above $100 a barrel for the first time since mid-May, as growing attacks along key shipping routes in the Middle East heightened concerns over prolonged supply disruptions.Around 7:30 am IST, Brent crude was trading at $107.70 a barrel, up 0.03%, while WTI crude stood at $102.50 a barrel, unchanged. Both benchmarks had surged more than 6% on Thursday, taking their weekly gains to nearly 13%, the steepest increase since the week ended July 17.The latest rise came as risks to oil shipments increased across both the Red Sea and the Gulf. The US national average price of diesel surpassed $6 a gallon for the first time ever on Thursday, according to price tracker GasBuddy, as the US-Iran war and Ukrainian attacks on Russia's refineries have squeezed supply.Analysts said the durability of the oil rally will depend heavily on China, the world's largest crude importer.China has stepped up purchases in recent weeks after months of subdued demand, boosting physical crude markets, ING analysts said in a note. Continued buying could amplify the impact of supply disruptions and push prices higher, while a pullback in imports could temper market gains.OPEC has lowered its forecast for world oil demand growth in 2026 to 380,000 barrels per day, according to a copy of its monthly report. It was the fifth straight downward revision to its demand growth forecast.OPEC oil output also fell by 640,000 barrels per day in August, a Reuters survey found, as Saudi exports faced new disruptions due to the war in Iran and a US blockade cut Iran's shipments.Meanwhile, US crude oil inventories fell by 391,000 barrels to 424.1 million barrels last week as refining activity continued to show strength, the Energy Information Administration said.