A tanker traveling off the coast of Oman in the Strait of Hormuz caught on fire early Tuesday morning after being struck by a projectile, the British military said.The United Kingdom Maritime Trade Operations center said the tanker had been hit near Limah, Oman, in the strait.It said the projectile hit the port side of the vessel while trying to traveling south out of the strait toward the Gulf of Oman.It said there was no environmental impact from the strike and that authorities were investigating.No one immediately claimed responsibility for the attack, though Iran is suspected of attacking at least two other vessels in the strait traveling on a route near Oman in recent days.