Iraq, Egypt and Lebanon all boycotted the 1956 Summer Olympics in Melbourne in protest of what?

The 1956 Summer Olympics, officially known as the Games of the XVI Olympiad, were an international multi-sport event which was held in Melbourne, Victoria, Australia, in 1956, apart from the equestrian events, which were held five months earlier in Stockholm. The 1956 Games were the first to be staged in the Southern Hemisphere and Oceania, as well as the first to be held outside Europe and North America. Melbourne is the southernmost city to host the games. Equestrian events could not be held in Australia due to quarantine regulations.

Egypt, Iraq, and Lebanon announced that they would not participate in the Olympics in response to the Suez Crisis when Egypt was invaded by Israel, the United Kingdom, and France after Egypt nationalised the Suez canal. Meanwhile, in 1956 the Soviet Union crushed the Hungarian Revolution, and the Soviet presence at the Games led to the withdrawal of the Netherlands, Cambodia, Spain, and Switzerland.