Non-crew members were in the cockpit of the Polish presidential plane that crashed in April near the western Russian city of Smolensk, killing everyone on board, the head of the Interstate Aviation Committee said on Wednesday.
"It was proven that non-crew members were in the cockpit," Tatyana Anodina said.
She said the voice of one person was identified while the others are being identified by Polish officials.
Anodina did not specify the number of people in the cockpit or their identities.
The Interstate Aviation Committee technical chief, Alexei Morozov, said Russian controllers had repeatedly warned the crew of Polish president plane of bad weather conditions and landing should be avoided.
"The lead controller warned the crew twice about fog at the airport, visibility of 400 meters, and that landing is impossible," Morozov said.
A Soviet-made Tu-154 aircraft crashed on April 10 when it attempted to land in thick fog, killing all 96 people on board, including President Lech Kaczynski and other top state officials.
Russian and Polish investigators and experts are jointly investigating the causes of the deadly crash, while Polish military prosecutors are conducting their own investigation.
MOSCOW, May 19 (RIA Novosti)
