Six sites have been picked for surface-to-air missiles, some in residential spots, including Bow and Leytonstone.
Campaigners say 1,000 people have signed a petition in protest.
The Ministry of Defence said the safety of the Games was paramount and a "broad range of community engagement" had taken place.
The sites, chosen from an original list of 100, include the Lexington Building in Tower Hamlets and the Fred Wigg Tower in Waltham Forest, east London.
The four other London sites identified as suitable for Rapier missiles are Blackheath Common; Oxleas Wood, Eltham; William Girling Reservoir, Enfield and Barn Hill in Epping Forest.
The proposals have yet to be confirmed.
Campaigner Chris Nineham said: "We don't believe they will add anything to security. If they are going to be used they will explode over some of the most densely populated areas in London."
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He added: "I simply don't believe that since 9/11 a security system hasn't been put in place to protect Canary Wharf and east London.
"If fighter jets are sent from another country I hope they will be taken out before they get to London."
When a major security exercise took place in April standing joint commander General Sir Nick Parker explained there must be a plan which could deal with "the unlikely but very serious threat" that might exist to the Olympic Park.
He explained: "It's an air threat, really categorised in two ways, the sort of 9/11 threat everyone knows about, and also for the lower, slower type of target which might pop up closer to the Olympic Park, which we would need to intervene."
Residents of Fred Wigg Tower, Leytonstone, have launched legal proceedings in the hope of preventing the installation of missiles on their building's roof during the Olympics.
East London residents opposed to plans to site surface-to-air missiles on roofs for added security during the Olympics, are to march through Bow.