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 Soviets killed thousands of Poles.
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."