"It clipped the tops of the trees, crashed down and broke into pieces," Antufiev told Russia-24 television.
Rafal Kiepuszewski, a journalist monitoring the situation in Poland, said the news came as a shock to the Polish people.
"The fact that much of the Polish political establishment appears to have been wiped out on this single flight has really come as a profound shock to the Polish nation," he said.
The Polish government delegation was on its way to the city of Smolensk to take part in the 70th commemoration of the Katyn massacre - where Russian forces killed more than 20,000 Polish soldiers.
Kaczynski has served as president of Poland since 2005. Prior to that, he was mayor of Warsaw, the Polish capital.
An emergency government session was being called in Warsaw to discuss the situation, while a crowd could be seen gathering in front of the presidential palace.
Smolensk local authorities investigating Saturday's crash said that pilot error may have been the cause of the crash.
"The pilot was advised to land in Minsk, but decided to land in Smolensk," Andrei Yevseyenkov, a spokesman for the local government said.
Chris Yates, an aviation expert, told Al Jazeera the the Tupolev Tu-154 is capable of operating in extreme weather conditions and able to land on unpaved airstrips.
"These things are built like tanks," he said via email correspondence.
"From early reports, it would seem to be a fluke accident, with the aircraft clipping trees in the descent."