Oil prices gained on Tuesday as the resumption of fighting between the US and Iran in the Middle East renewed fears of supply disruptions from the world’s key crude-producing region. Brent crude futures were up 56 cents, or 0.6%, to $91.05 a barrel at 0044 GMT, while US West Texas Intermediate crude was up 83 cents, or 1%, to $86.59. In the previous session, Brent closed up 2.7%, at one p