Ukraine's defence minister says he never doubted that a missile from his country was responsible for downing a Russian passenger jet.
However, the statement is a sharp departure from his previous stance, in which he claimed it was barely possible a Ukrainian missile was to blame.
Defense Minister Oleksandr Kuzmuk says it is time to find out why the missile that brought down the Tu-154 earlier this month went astray.
"There is another matter: What caused this, what fatal coincidence of circumstances _ and all officials are working on this now," Mr Kuzmuk said.
The Tu-154 airliner, en route from Israel to Novosibirsk in Siberia, went down on October 4 in the Black Sea after an explosion. All 78 people on board, most of them recent Russian immigrants to Israel, were killed. The remains of 15 people were recovered. PA