BRUSSELS — Belgian prosecutors announced Saturday they have charged three men with terror offenses over the suicide attacks on the Brussels airport and subway, as organizers cancelled a solidarity rally at the government’s request because police are too strapped to cope. At a news conference in Brussels, officials confirmed that 24 of the 31 people killed in the attacks Tuesday had been identified, and a doctor who had served in Afghanistan said he and his colleagues have been shocked by the extreme burns suffered by some of the 270 people wounded. Federal prosecutors said a man identified as Faycal C., who was arrested Thursday, has been charged with “involvement in a terrorist group, terrorist murder and attempted terrorist murder.” Belgian media say he is Faycal Cheffou, the man in the light vest and hat pictured on security video with two men who blew themselves up at the airport.