DOHA - Three tankers including a Qatari LNG vessel were struck within hours in the Strait of Hormuz, maritime monitors and Qatar said on July 7, with peace mediator Doha denouncing an “unacceptable” Iranian attack.An “unknown projectile” hit a tanker overnight, causing a fire, before two more were hit, at least one by a drone, British maritime security agency UKMTO said.The string of attacks after more than a week of respite revived concerns about freedom of navigation after Iran lifted its blockade of the vital waterway following a fragile ceasefire with the United States.All three vessels were struck close to Oman.Oman had proposed a temporary transit corridor hugging its coastline in an initiative opposed by Iran, which wants to charge ships using the narrow waterway.Qatar, which helped