Article published on the 2008-08-15 Latest update 2008-08-15 13:43 TU
The US has said the system will protect itself and Europe against long range missile attacks by what it calls "rogue states", such as Iran.
President George Bush "was very pleased with this development," a White House spokeswoman told reporters in Washington.
The move has infuriated Moscow, which says it will be forced to redirect its missiles at Poland. Russian Foreign Minister Sergei Lavrov is reported to have cancelled a scheduled visit to Warsaw after the deal was announced.
A Russian Foreign Minstry official quoted by Interfax news agency says that the timing, coinciding with the Georgia conflict, proves that the project has "no relation to the Iranian missile threat" and is in reality aimed at his country.
Washington also plans to base a radar facility in the neighbouring Czech Republic by 2011-2013 to complete a system already in place in the United States, Greenland and Britain.
According to opinion polls, the majority of the population of both countries oppose the system being sited in their countries.
"They are indeed against," Moscow-based analyst Maria Lipman told RFI. "Actually for America to begin implementing its plans to install elements of its anti-missile defence needs ratification of these agreements by the parliaments of all three countries - the United States, the Polish legislature and the Czech legislature. It is not at all clear whether, in fact, such ratifications can be achieved soon."
The Czech Republic and Poland were Soviet satellites until 1989, before transforming into staunch US allies when the communist bloc collapsed. They both joined Nato in 1999 and the European Union in 2004.