Iran’s Revolutionary Guard Corps said on Tuesday it reserved the “legitimate and definite” right to retaliate against any ceasefire violations by the U.S., adding that its air defence units had shot down a U.S. MQ-9 drone and fired at a F-35 fighter jet that had entered Iranian airspace, state media reported. It claims the F-35, the worlds most advanced and lethal fighter jet, was forced to leave its airspace. The IRGC added that it also fired at an RQ4 intelligence collection drone. This comes after the US carried out what it called “self-defence” strikes in southern Iran overnight, threatening a fragile ceasefire between Washington and Tehran. The strikes hit coastal towns near ​the Strait of Hormuz which remains closed as peace negotiations continue. Targets also included missile launch sites and and Iranian mine-laying boats. The key waterway has been closed for almost three months as part of Iran’s retaliation to joint US-Israeli strikes on several of its key sites. The US responded by blocking Iranian ports in the strait. “U.S. forces conducted self-defense strikes in …