Polish and US negotiators were wrapping up their latest round of talks Thursday on a proposed US missile defense base, and Poland's foreign minister said the two sides have narrowed their differences. Talks about a US plan to build a missile interceptor base in northern Poland have been dragging over Polish demands for additional security guarantees - demands now underlined by the fighting between Russia and Georgia. "Our positions have become closer," Foreign Minister Radek Sikorski said after meeting chief US negotiator John Rood late Wednesday. "There is a change in the US position," Sikorski said, without elaborating. "Poland is negotiating in good faith and an agreement is possible." But while the gap is narrowing in the talks, Sikorski stressed that "I cannot predict their outcome." Washington wants to place 10 interceptor missiles in northern Poland and a linked radar tracking base in the neighboring Czech Republic. The Czech government has agreed a deal, but faces a battle to win parliamentary approval. The US says the defense system is needed to protect Europe and the United States from possible future attacks from Iran. Moscow has said that the planned US facilities are aimed at undermining Russia's own missile potential, and has threatened an unspecified "military technical" response. Citing that threat, Poland has demanded the permanent stationing of US Patriot missiles in Poland and US aid for Polish air defenses. It rejected a previous offer of a temporary lease of Patriot missiles. Prime Minister Donald Tusk has said the Russian attacks in Georgia over the past week justified Poland's demands. Sikorski reiterated that argument Wednesday, saying "The increase in international tension that we are dealing with now, but which we had not expected, makes the security guarantees ... an issue even more important than before."