Poland is in mourning over the deaths of President Lech Kaczynski and much of its defence establishment in a plane crash in western Russia.
All 97 people on the jet, who had been due to attend a memorial for victims of a wartime massacre, died when it crashed in fog near Smolensk air base.
Russian officials say pilots ignored warnings they were flying too low.
A week of mourning has been called in Poland where a two-minute silence will be held at noon (1000 GMT).
