A plane carrying Polish President Lech Kaczynski has crashed near a Russian airport, officials say.
Russian media reported that 87 people were killed in the crash near Smolensk, and a regional governor was quoted as saying there were no survivors.
Polish officials said Mr Kaczynski was on board along with his wife Maria and several senior government figures.
They were in Russia to mark the 70th anniversary of the Katyn massacre, when the Soviets killed thousands of Poles.
Plane 'hit trees'
The Russian emergencies ministry told Itar-Tass news agency the plane crashed at 1056 Moscow time (0656 GMT).
Ministry spokeswoman Irina Andrianova said it had been flying from Moscow to Smolensk, but had no details on the identities of those killed.
Smolensk regional governor Sergei Antufiev told Russian TV that no-one had survived.
"As it was preparing for landing, the Polish president's aircraft did not make it to the landing strip," he said.
"According to preliminary reports, it got caught up in the tops of trees, fell to the ground and broke up into pieces. There are no survivors in that crash.
"We are clarifying how many people there were in the [Polish] delegation. According to preliminary reports, 85 members of the delegation and the crew."
The BBC's Adam Easton in Warsaw says the president was flying in a Tupolev 154, a plane that was designed in the 1960s and capable of carrying more than 100 passengers.
The Polish Foreign Ministry said the president and his wife were aboard the plane.
Central bank governor Slawomir Skrzypek was also said to have been on board.
Mr Kaczynski has been a controversial figure in Polish politics, advocating a right-wing Catholic agenda.
He has opposed rapid free-market reforms and favoured retaining social welfare programmes.