WARSAW, Jan. 10 (Xinhua) -- The destruction of left wing of the Tu-154 aircraft was a result of internal explosion, a Polish subcommittee investigating the crash of the Polish president's plane said in a report on Wednesday.

According to subcommittee's spokesperson, Marta Palonek, the conclusions of the reports were: the destruction of left wing was a result of internal explosion, there were several sources of explosion, and the birch had no impact on the original destruction of the wing.

Frank Taylor, an international expert of the subcommittee confirmed the adopted conclusions. The final technical report is to be ready in April.

On April 10, 2010, a Polish government plane crashed near a military airfield in Smolensk, Russia. Among the victims were President and First Lady, scores of senior government officials and military commanders.

The Russian Interstate Aviation Committee released the final investigation report in 2011 saying one of the main causes of the plane crash was the crew's failure to route the plane to an alternative airport in spite of receiving the information about weather conditions at Smolensky-Severny Airport.

In order to reexamine the cause of the fatal crash of the Presidential aircraft, Poland established the Subcommittee on Reexamination of the Crash of TU-154 in 2016. It consists of 21 members and cooperates with foreign experts.