STATE DEPARTMENT --- U.S. officials say the United States and Poland have reached a tentative agreement under which part of a U.S. missile defense system will be based on Polish soil. The deal to station interceptor missiles in Poland still requires top-level Polish government approval.>> A senior Bush administration official says the two sides have finalized the text of a draft accord, under which Poland will join the Czech Republic in hosting a regional U.S. defense system aimed against an anticipated long-range missile threat from Iran.>> No terms of the tentative deal were disclosed though Poland had been seeking, in return for accepting the U.S. system, a multi-billion dollar upgrade of its air defense capabilities.>> The senior official said the deal was hammered out late Tuesday after two days of closed door Washington meetings this week between State Department officials and officials of the Polish defense and foreign ministries.>> The U.S. plan calls for the stationing of ten interceptor missiles in Poland and an associated advanced radar system in the Czech Republic. A tentative agreement with the Prague government was reached several weeks ago.>> The planned system has been strongly opposed by Moscow, which contends, despite U.S. denials, that the anti-missile system would undercut its strategic nuclear deterrent.>> In a talk with reporters Wednesday, U.S.