Human error was most likely to blame for the crash of Polish President Lech Kaczynski's airplane in western Russia in which 132 people including the president died, a Russian security source said.
"A mistake by the crew during landing maneuvers has supposedly caused the crash," the source in the regional security bodies, who refused to be identified, told RIA Novosti.
There have been no official suggestions of what had caused the crash.
MOSCOW, April 10 (RIA Novosti)