WARSAW, July 13 -- Poland has narrowed its proposal for a new permanent United States military base to two sites in western Poland, Deputy Defense Minister Cezary Tomczyk said Monday, naming Greater Poland and Lower Silesia as the locations Warsaw considers most viable.

"We have selected two most likely locations for an American base. These are Greater Poland and Lower Silesia," Tomczyk said in an interview with RMF FM radio. A final decision has not been made, he added, saying "another location may emerge." The announcement comes weeks after Poland formally submitted its base proposal to Washington in early June.

The selection of western rather than eastern locations is a deliberate strategic choice. Tomczyk said a western base would b...