Russian President Dmitry Medvedev arrived in Warsaw Monday for the first state visit by a Kremlin leader in Poland in nine years, signalling a warming of bilateral ties. His visit comes eight months after the April 10 air disaster in Smolensk, western Russia, which claimed the lives of Polish president Lech Kaczynski and 95 others heading to a commemoration of a Soviet World War II massacre of thousands of Polish officers. A warming of bilateral ties between Moscow and Warsaw emerged in the wake of the crash. Medvedev's two-day visit to Poland, an increasingly important member of the European Union since its 2004 entry, is being seen as a step forward in bilateral ties and EU-Russia relations. Poland and its Soviet-era master Russia have had uneasy relations since the demise of communism and the collapse of the Soviet Union 20 years ago. Particular points of tension have been Poland's membership of the NATO Western defence alliance since 1999 and the European Union since 2004. 