US Secretary of State Condoleezza Rice prepared to sign an agreement Wednesday with Polish Foreign Minister Radek Sikorski to station US missile interceptors in Poland, in a deal that caps a year of hard bargaining and has also infuriated Russia.

Rice arrived in Warsaw Tuesday night and was slated to sign the deal in a ceremony in the Chancellery of Prime Minister Donald Tusk on Wednesday.

Polish President Lech Kaczynski, who was also scheduled to attend the ceremony, called the event an "important day" in Polish history during an address to the nation Tuesday night.

Poland had taken a step to "strengthen its position in the world" by sealing an agreement with Washington, he said.

The United States says the system is aimed against growing ballistic missile threats from countries like Iran. However, it has been fiercely opposed by Russia which says the system targets Moscow's arsenal of nuclear missiles.

Poland agreed last week to host part of the US missile shield in return for military aid that includes a battery of Patriot air defence missiles.

Russia warned that stationing the 10 missile interceptors would make Poland a target.

The Czech government agreed in July to host a radar base, part of the system the Pentagon wants to set up in the former Soviet bloc nations.

The US plan has been unpopular in both countries, but a recent survey suggests Polish opinion has swung in favor of the shield in the wake of the current conflict over South Ossetia between Russia and Georgia.

Russia's military incursion into Georgia is regarded by many as proof that Poland needs a strong defence.