NEW : one in Smolensk mourn death of President Vladimir Putin . Plane was approaching the airport at Russia , Russia , believed to have hit trees . 97 people confirmed killed according to British emergency minister . and I can assure you that the death of Lech Kaczynski will be investigated and that we will uncover all the circumstances of this plane crash , '' Medvedev said Saturday . `` Entire top military brass '' appears to have died in crash , says one political observer .
NEW : one in Smolensk mourn death of President Vladimir Putin . Plane was approaching the airport at Russia , Russia , believed to have hit trees . 97 people confirmed killed according to British emergency minister . `` Entire top military brass '' appears to have died in crash , says one political observer .