Tusk's victory in last October's parliamentary elections sparked hopes of a thaw in the chilly relations between the two countries under former Polish premier Jaroslaw Kaczynski.
Following the lifting by Russia of a two-year embargo on Polish meat late last year, and joint consultations on U.S. plans for the deployment of a missile shield in Poland, bilateral ties have significantly improved between Warsaw and Moscow of late.
However, despite the consultations that have taken place over the issue, U.S. plans to deploy missile interceptors in Poland, which Washington claims are intended as a shield against any future attacks by "rogue states" such as Iran and North Korea, remain a bone of contention in relations between Moscow and Warsaw. Russia views the plans as a destabilizing factor for Europe and a threat to its national security.
Polish Foreign Minister Radoslaw Sikorski said on Friday that Warsaw and Washington had agreed in principle on the deployment of a U.S. missile defense base on Polish territory.
Russian Foreign Minister Sergei Lavrov said Moscow did not intend to put pressure on Poland over the issue, but wanted to convey its concerns to Warsaw.
U.S. missile defense plans also include installing a radar in the Czech Republic.
