Russia has handed Poland thousands of new documents on the investigation into the plane crash that killed Polish President Lech Kaczynski in April.

Russian Deputy Prosecutor General Alexander Zvyagintsev says the documents include witness interviews, photographs and other data from the crash in western Russia.

The documents were given Thursday to a Polish delegation led by chief military prosecutor Krzysztof Parulski.

Earlier this month, Polish Prime Minister Donald Tusk complained about what he called Russian delays in turning over the evidence, which is crucial to a parallel Polish probe.  The April 10 crash killed President Kaczynski, his wife and 94 others outside the Russian city of Smolensk.

Officials say poor visibility was a major factor in the crash.  But they are also seeking to learn whether President Kaczynski or others pressured the pilots to attempt a landing despite heavy fog.

Some information for this report was provided by AP, AFP and Reuters.