Surface-to-air missiles could be deployed at five sites across London, as preparations begin for a major Olympics security exercise.
The Lexington Building in Tower Hamlets and the Fred Wigg Tower in Waltham Forest, both in east London, are sites.
Also named are Blackheath Common and Oxleas Wood, both in south-east London; William Girling Reservoir in Enfield; and Barn Hill in Epping Forest.
It comes as details were given of a major exercise taking place this week.
Exercise Olympic Guardian is being held on land, sea and air in the London and Weymouth areas between 2 and 10 May.
It will see a wide range of capabilities rehearsed.
The Ministry of Defence has stressed that the government has not yet decided to deploy ground-based air defence systems during the Games.
Brian Whelan, a resident of one of the east London estates, said firing the missiles "would shower debris across the east end of London".
Standing joint commander General Sir Nick Parker said the decision on the missiles would be taken "at the very highest political level".
Referring to this week's exercise he said the military advice to the government "will depend on the success of that test".
Defence Secretary Philip Hammond said: "Support for the Olympic Games will be an important task for defence in 2012 and this exercise is about pushing our people and our systems to the limit to ensure that we are ready for the challenge.
"The majority of this exercise will be played out in full view of the public and I hope that it will have a secondary effect of reassuring the British people that everything possible is being done to ensure this will be a safe and secure Olympic and Paralympic Games."
