President Lech Kaczynski and scores of other senior Polish figures have been killed in a plane crash in Russia.
Polish and Russian officials said no-one survived after the plane apparently hit trees as it approached Smolensk airport in thick fog.
Russian media reports said the pilots ignored advice from air traffic control to divert to another airport.
Poland’s army chief, central bank governor, MPs and leading historians were among more than 80 passengers.
Prime Minister Donald Tusk said the crash was the most tragic event of the country’s post-World War II history.
The Polish delegation was flying in from Warsaw to mark the 70th anniversary of the Katyn massacre of thousands of Poles by Soviet forces during WWII.
The BBC’s Adam Easton, in Warsaw, says the crash is a catastrophe for the Polish people.
He says Prime Minister Tusk was reportedly in tears when he was told. …
A government spokesman said that according to the constitution there would be an early presidential election, and the speaker of the lower house of parliament, Bronislaw Komorowski, would be acting president.
In Warsaw, people gathered outside the presidential palace to lay flowers and light candles.
“I’m all broken up… it cannot be expressed in words,” Ewa Robaczewska told Reuters news agency. …
The Russian emergencies ministry told Itar-Tass news agency the plane crashed at 1056 Moscow time (0656 GMT) as it was coming in to land.
Smolensk regional governor Sergei Antufiev told Russian TV that no-one had survived.
… Polish TV worker Slawomir Wisniewski said he had seen the crash from his hotel near the airport.
“I saw through the fog, the aeroplane flying very low with the left wing pointing to the ground,” he said.
“I heard something being broken and then that thudding sound. Two flashes of fire next to each other.”
Russian media carried claims that the plane’s crew were at fault for the crash.
“Flight controllers… suggested that the plane be forwarded to Minsk but as far as we know the crew took an independent decision to land the plane in Smolensk,” Smolensk regional government spokesman Andrei Yevseyenkov told Russian TV.
Russian officials said 97 people were killed in the crash, including eight crew. …
Mr Kaczynski’s twin brother, Jaroslaw, a former prime minister and now head of the main opposition party, was said to be “devastated”, an aide told AFP news agency.
Lech Kaczynski, who had fewer powers than the prime minister but had a significant say in foreign policy, was a controversial figure in Polish politics.
He had advocated a right-wing Catholic agenda, opposed rapid free-market reforms and favoured retaining social welfare programmes.