The upper chamber of the Czech parliament on Thursday approved a deal with Washington to accept a U.S. missile defense installation.

The deal still needs approval by the lower chamber, where the vote is expected to be close because the governing coalition has too few seats to guarantee passage. That vote is not expected before the end of the year.

The proposed U.S. missile defense system calls for a tracking radar in the Czech Republic and 10 interceptor missiles in Poland as part of a shield designed to protect the region from possible attacks from Iran.

The Senate approved both treaties involved in the deal — the main bilateral treaty allowing the United States to build a radar base near Prague and the second, "complementary," treaty that deals with the legal status of U.S. soldiers to be deployed at the base.

In two separate votes in the 81-seat chamber, 49 senators voted in favor, and 31 were against in each case.

Parliamentary ratification is also needed in Poland.

Russia is fiercely opposed to the plans, saying U.S. military installations in former Soviet satellites pose a threat to Russian security.

It recently threatened to install short-range missiles close to EU borders in response to the U.S. missile defense plans. Russian President Dmitry Medvedev later suggested that if Washington halts its plans, Moscow would do the same.

The administration of President-elect Barack Obama has not given an assessment of the deals brokered under President George W. Bush.