Polish President Lech Kaczynski, 60, and some of the country's highest military and civilian leaders died on Saturday when the presidential plane crashed as it came in for a landing in thick fog in western Russia, killing 97 people, officials said.
Russian and Polish officials said there were no survivors on the 26-year-old Tupolev, which was taking the president, his wife and staff to events marking the 70th anniversary of the massacre in Katyn forest of 22,000 Polish officers by Soviet secret police.
The crash devastated the upper echelons of Poland's political and military establishments. On board were the army chief of staff, national bank president, deputy foreign minister, head of the National Security Office, deputy parliament speaker, civil rights commissioner and at least two presidential aides and three lawmakers.
Reflecting the grave sensibilities of the crash to relations between the two countries, Russian Prime Minister Vlad-imir Putin personally assumed charge of the investigation.
Andrei Yevseyenkov, spokes-man for the Smolensk regional government, said Russian dispatchers asked the crew to divert from the military airport in North Smolensk and land instead in Minsk, the capital of neighbouring Belarus, or in Moscow because of the fog.
Air Force General Alexander Alyoshin confirmed the pilot disregarded instructions to fly to another airfield.
Russia's Emergency Minister Sergei Shoigu said there were 97 dead, of which 88 were part of the Polish state delegation.
The deaths were not expected to directly affect the functioning of the Polish government as the president's domestic duties are chiefly symbolic.
Poland has long discussed replacing the planes that carry the country's leaders but said they lacked the funds.