Oil prices jumped more than four percent on Monday after a fresh flare-up between the United States and Iran, threatening their already fragile truce and raising concerns about the stability of the Strait of Hormuz. The renewed hostilities followed an Iranian attack on a commercial ship in the strait, prompting Iran's Revolutionary Guards to declare the waterway closed until further notice. The US Central Command countered that the strait remains open to lawful transit and that their forces are prepared to ensure freedom of navigation. Both main oil contracts spiked as much as 4.5 percent, fanning concerns that inflation could force central banks to hike interest rates. However, analysts noted that oil prices are unlikely to reach the lofty levels seen after the war's outbreak in March, due to slow demand recovery and increased supply from OPEC and stranded-tanker releases.