Poland and the Czech Republic are being considered for the European base of a US anti-missile shield, although opposition to the plan is rising in both countries.
The US is also considering basing interceptor missiles and radar in Bulgaria, Hungary and Turkey.
A Russian general quoted by daily newspaper Izvestia said Moscow would view the deployment of US missiles in eastern and central Europe as a security threat and would take retaliatory measures.
Yevgeny Buzhinsky, the head of the Russian defence ministry's international military co-operation department, urged the US and its allies to refrain from unilateral action and negotiate with Moscow.
"The deployment of missile defence near the Russian borders could pose a real threat to our deterrent forces," Buzhinsky said in the article.
"We would view that as an unfriendly gesture on behalf of the United States, some eastern European nations and Nato as a whole. Such actions would require taking adequate retaliatory measures of military and political character," Buzhinsky said.
The European site would be the first expansion outside the United States of an unproven missile defence system aimed at repelling any limited long-range missile attack from North Korea or the Middle East.
Buzhinsky would not elaborate on how Russia would respond to any deployment, but warned
"a buildup of military potential near the Russian borders couldn't strengthen European security".
"It's still not too late to analyse possible negative consequences of unilateral actions in the security sphere and try to avert them," Buzhinsky wrote in the article.
"Advertising missile defence capabilities... would make these sites an attractive target for terror attacks"
Yevgeny Buzhinsky, Russian defence ministry official
"Advertising missile defence capabilities, the importance of these facilities for the United States and a strong public reaction that can be caused by their destruction would make these sites an attractive target for terror attacks," he said.
The US missile defence system employs radar to detect enemy missile launches and guide interceptors to their targets.
The command centre is based in the southwestern US state of Colorado, and interceptor missiles are located in Alaska and at Vandenberg air base in California.
General Henry Obering, the head of the US missile defence agency, said last month that he expected to make recommendations in a matter of months on where to position the missiles and radars in Europe.