Polish President Lech Kaczynski and a high-level delegation were killed when a plane carrying 97 people crashed in thick fog as it was approaching a Russian airport on Saturday morning.
Russian authorities said there were no survivors in the catastrophe. The Polish President's Tu-154 passenger jet went down after its wing scraped treetops about a kilometre short of the runway near the Russian city of Smolensk.
Russian investigators suspect pilot error as the cause of the crash.
Flight controllers alerted Mr. Kaczynski's plane about heavy fog at Smolensk and advised it to divert to Minsk or Moscow, Russian authorities said. Minutes earlier, the control tower redirected a Russian IL-76 transport aircraft from Smolensk to another airport. But the Polish pilot insisted on landing in Smolensk.
The plane kept circling the airport, and on the fourth attempt crashed.
Mr. Kaczynski, 60, was on his way to a memorial service at Katyn, near Smolensk, where Polish army officers were executed on the orders of Soviet dictator Joseph Stalin 70 years ago during World War Two. Three days earlier Polish Prime Minister Donald Tusk and Russian Prime Minister Vladimir Putin attended a joint memorial service at Katyn. Mr. Kaczynski was not invited because of his strained relations with both leaders and decided to lead a separate ceremony.
In a televised address to the people of Poland, Russian President Dmitry Medvedev said he was shocked and grieved the death of the Polish President. Mr. Medvedev promised to carry out a thorough investigation jointly with Polish authorities. He named Mr. Putin to head a government commission to probe the crash and dispatched top emergency and investigation officials to the site.
The crash is a tragedy of staggering proportions for Poland as it wiped out the cream of its elite. Along with the President and his wife, dozens of top officials were on board, including the Army Chief of Staff and several senior military brasshats, the head of the country's Central Bank, a Deputy Speaker of Parliament, and a Deputy Foreign Minister.
Under the Polish Constitution, the Speaker of the Sejm, Poland's Lower House of Parliament, becomes the interim head of state pending snap presidential elections within two months.
The 20-year-old Tu-154 had undergone a scheduled overhaul at a Russian factory late last year and had been cleared to fly for six years before next maintenance.
