Investigators have recovered two black boxes from a plane that crashed in western Russia, killing 97 people. Polish President Lech Kaczynski, his wife and other high ranking officials were among the victims. Russia and Poland have both declared a day of mourning.

Mourners paid tribute to crash victims on Saturday in Russia and Poland. Flowers and lit candles filled the streets in Warsaw, where thousands prayed for their those killed.

Russian President, Dmitry Medvedev, and Prime Minister, Vladimir Putin, also lit candles and prayed.

Later, Putin arrived at the crash site and directed search efforts.

Putin said, "We need to do everything possible to determine the cause of this tragedy as soon as possible. That's the first task. The second is to help the relatives of those killed."