The 40-minute phone conversation between Polish Prime Minister Donald Tusk and Cheney took place Thursday, one day after negotiators struck a tentative agreement to place the missile base on Polish soil, RIA Novosti, the Russian information agency, reported Friday.

Polish leaders are pressing for more U.S. financial assistance to modernize the Polish air defense system, Polish television reports indicated. The United States already gives Poland $27 million annually in military funding, and the Bush administration has offered another $20 million per year.

Besides locating 10 interceptor missiles in Poland, the United States wants to locate a radar installation in the Czech Republic as part of its missile shield. The Czech government has agreed to the plan, pending parliamentary approval.

Earlier this week, the United States and Lithuania revealed they were conducting talks about a possible missile interceptor base in the Baltic state if the U.S. deal with Poland collapses.

Russia opposes the missile shield, saying it threatens Russia's national security, RIA-Novosti said. The United States said the shield is necessary to deter attacks by rogue states.