Oil prices rose for a fifth day on Thursday as Iran-backed Houthi militants struck two Saudi oil tankers as part of a naval blockade on Saudi Arabia, threatening to unleash more chaos on global fuel supplies.The attack risks creating a second chokepoint on the world's oil supplies amid Iran's near-closure of the Strait of Hormuz, through which around 20 per cent of the globe's oil and liquefied natural gas usually flows.The Yemeni group said it deployed missiles and drones to strike the vessels Encelia and Layla, accusing them of violating its embargo of the Red Sea. It followed the Houthis' announcement this week they were imposing a maritime blockade on Saudi Arabia - threatening to unravel a four-year ceasefire with the kingdom.Brent crude futures rose $2.42, or 2.6 per cent, to $96.49 by 6.40am GMT, the highest since June 8. It comes as Donald Trump unleashed a 12th consecutive night of strikes against Iran, threatening intense attacks on the nation's power plants and bridges, with the Islamic Republic also firing at targets in the Middle East. The Houthis control ⁠northern Yemen, including territory along the Bab el-Mandeb, a vital maritime trade route that links the Red Sea to the Gulf of Arden and the Indian Ocean.While the rebels have not formally announced the closure of the waterway, as some had feared might happen, the militia group’s threat to ships using Saudi ports has raised serious concerns over the safety of navigating a channel used by 7 per cent of global maritime traffic.