DUBAI — A tanker caught fire off the coast of Oman after Iran’s Revolutionary Guards allegedly fired at least two missiles at commercial ships transiting through the Strait of Hormuz overnight, marking an escalation that threatens to complicate negotiations to end the US-Iran war, according to a senior US official.The ships suffered significant damage but had no casualties, Axios and the Wall Street Journal reported citingthe US official.The United Kingdom’s Maritime Trade Operations Center (UKMTO) said earlier that a tanker has caught fire after being struck by a projectile off the coast of Oman in the Strait.Iranian television said the liquefied natural gas tanker came under attack after ignoring warnings, but Tehran did not directly claim the assault.One of the vessels under attack appears to be Al Rekayyat, a liquefied natural gas tanker owned and managed by Nakilat the shipping arm of Qatar’s LNG industry, the WSJ said, adding that the ship had been hit on the port side, at the top of the engine room.The vessel was at the mouth of the strait, in the Gulf of Oman, when it was attacked, the WSJ said.The attacks early on Tuesday was the latest targeting a vessel moving through the Gulf’s critical waterway, through which a fifth of the world’s oil and natural gas passed before the US-Israel war on Iran began in late February.Tehran has repeatedly declared that only its approved route through the Strait of Hormuz is safe, and it is suspected of attacking other ships that have used another route close to the Omani shore.The attacks come as Iranians mourn Ayatollah Ali Khamenei, the former supreme leader killed at the start of the Iran war. They also follow stepped-up threats by the powerful paramilitary force, warning vessels not to transit the waterway using a route cleared by the US military near the coast of Oman.Talks between Iran and the United States on a permanent end to the war appear to be on hold until after the burial of Khamenei, who was killed at the beginning of the US-Israel war on Iran on February 28.Authorities flew Khamenei’s body to the seminary city of Qom overnight, where mourners honored him on Tuesday.