Oil prices hit $100 a barrel for the first time since May as the escalating conflict in the Middle East reignited fears over global energy supplies. Brent crude - the global benchmark for oil prices - rose more than 6% on Thursday following several days of increases as the US stepped up military strikes against Iran. Prices spiked after Houthi militia in Yemen attacked oil tankers in the Red Sea, threatening a key export route that Saudi Arabia has used to bypass the Strait of Hormuz.