A Polish report on the 2010 plane crash in Russia that killed President Lech Kaczynski and 95 others says Russian air traffic controllers gave incorrect and confusing landing instructions to pilots, a finding that could test already strained ties between the neighbours. It challenges a Russian aviation commission report published in January that put sole blame for the disaster on Polish officials and struck Poles as an attempt to avoid any responsibility for the plane crash in heavy fog at a rudimentary airport near Smolensk. Since then, Poles have eagerly awaited their own experts report, hoping it would create a more balanced picture of the crash. The accident on April 10, 2010, killed dozens of senior officials along with the president and first lady, in the worst Polish disaster since World War II. The Polish report presented on Friday does not shy away from putting most of the blame on Polish officials and procedures.