"One of the "sides" in the separation vdsa to the desired distance and hit Baku fuel second stage, which led to the rupture of the tank and the destruction of the first degree", he said.
The accident occurred at Baikonur October 11 during startup.
The accident was the first involving a manned launch since the Soviet era and delivered another blow to the image of Russia's space programme after embarrassing losses of satellites and of an unmanned cargo ship in 2015.
Skorobogatov, who heads TsNIIMash, a Russian research institute specialising in spacecraft and missile development, said the commission ruled out that the problem happened at a production facility.
A Russian space investigation has found that sensor that was damaged during assembly forced a Russian rocket to abort its trip two minutes after it was launched, a top Russian official said Thursday.More news: 'Godfather of Taliban' Maulana Samiul Haq shot dead in Rawalpindi
The rocket producer will also take apart two other rockets which have been recently assembled and are due to launch in the coming weeks and then reassemble them, Skorogobatov said.
Russian officials pledged to improve oversight during assembly of the spacecraft.
Krikalyov said the astronauts now on the ISS - Alexander Gerst of the European Space Agency, NASA's Serena Aunon-Chancellor, and Sergey Prokopyev of Roscosmos - are expected back on Earth "around December 20".
"In general, the reputation of our space industry will not be hurt by this case, because we will make sure that these situations don't happen (again)", he added.
Russian Federation is the only country now able to send astronauts to the International Space Station, and the accident caused it to suspend all launches until getting to the bottom of the rare failed manned launch.
"Every accident has a name and surname (of the guilty party)", he said.
The next astronauts heading to the ISS will be Russia's Oleg Kononenko, Canadian astronaut David Saint-Jacques and NASA astronaut Anne McClain.