Polish politicians have held rival observances for former President Lech Kaczynski and 95 others killed two years ago in a plane crash in Russia.
President Bronislaw Komorowski laid flowers to the victims at the Presidential Palace.
Kaczynski's twin brother and opposition party leader, Jaroslaw Kaczynski, laid a wreath at a different site at the palace.
The rival observances come as opposition supporters say the crash was not an accident and put forth assassination theories.
Meanwhile, Georgia unveiled a bust to commemorate Lech Kaczynski, a firm supporter of Tbilisi in its 2008 war with Russia.
Kaczynski's plane crashed on April 10, 2010, in Smolensk as he led a delegation to Russia to honor 22,000 Polish officers murdered by Josef Stalin's secret police at the start of World War II in the Katyn forest.
Based on reporting by AFP and AP