Secretary of State Condoleezza Rice listens to a reporter's question during a joint news conference with South Korea's Foreign Minister Yu Myung-hwan at the Foreign Ministry in Seoul June 28, 2008. REUTERS/Jo Yong-Hak

PRAGUE (Reuters) - The United States and the Czech Republic signed a treaty on Tuesday allowing Washington to build part of a missile defense shield in the central European NATO state, despite tough opposition from Russia.

Secretary of State Condoleezza Rice and Czech Foreign Minister Karel Schwarzenberg signed the deal to build a radar station southwest of Prague, part of a system which Washington says is aimed at shooting down missiles that may be fired from countries such as Iran.