Gleb Garanich / Reuters
Relatives looking at a wall with the names of the Katyn dead during a ceremony in Kharkiv, Ukraine, on Saturday.
The death of President Lech Kaczynski, his wife Maria and 94 others, mostly senior state officials, in Smolensk sparked a wave of sympathy in Poland and Russia.
Warsaw's efforts to improve relations — traditionally strained over history, energy and security issues — with its communist-era overlord Moscow have gathered pace since.
But a series of hiccups has reversed the trend, and a new CBOS poll showed 28 percent of Poles are now negative about Warsaw-Moscow ties, while 26 are positive. The remainder said they could not say either way.
A CBOS survey in May showed that twice as many Poles assessed Polish-Russian ties as positive than held the opposite view.
"The actions of the Russian side aimed at establishing the reason of the plane crash are viewed negatively by more than half of Poles (56 percent), compared with less than one-third (31 percent) who think they are good," CBOS said in a statement.