"According to reconnaissance data, a Ukrainian army battalion of Buk air defense systems was deployed near Donetsk on Wednesday morning,” the source said.
The source added that armed militia fighting Kiev-led forces in eastern Ukraine does not have Buk systems, which are capable of shooting down aircraft flying at altitudes up to 25 kilometers (82,000 feet).
Earlier the same day, adviser to the Ukrainian Interior Minister wrote on his Facebook page that a Buk surface-to-air missile system was indeed used to down the plane, but insisted that the self-defense forces had done that.
According to various reports, a Malaysia Airlines Boeing-777 flying from Amsterdam to Kuala Lumpur crashed near the city of Donetsk in eastern Ukraine Thursday. There were 280 passengers and 15 crew members on board.
Malaysia Airlines confirmed that it had lost contact with its plane when it was above the Ukrainian airspace.
“Malaysia Airlines has lost contact of MH17 from Amsterdam. The last known position was over Ukrainian airspace. More details to follow,” the company said on Twitter.
Wintesses from the town of Torez in the Donetsk Region told RIA Novosti that plane wreckage and dead bodies have been located in the area.