DUBAI: A crude oil tanker in the Arabian Gulf caught fire Wednesday night, prompting a warning from British naval officials to “exercise extreme caution.” The United Kingdom’s Maritime Trade Operations said the fire struck the vessel northwest of Sharjah. Emirati officials said they were working to put out the blaze some 34 kilometers off the coast of Sharjah. The state-run WAM news agency later described the tanker as unloaded and said its crew had been rescued.