Updated

MOSCOW (AP) — Russia on Monday handed over to Poland copies of cockpit conversation recorders and other materials related to the investigation into the plane crash that killed Polish President Lech Kaczynski.

Polish Interior Minister Jerzy Miller thanked Russian investigators for their cooperation, but said Poland needed access to all documents related to the crash in order to conduct its own probe.

It was not immediately clear how much information remained to be handed over, but Russian officials said their probe was proceeding as quickly as possible.

The April 10 crash killed Kaczynski, his wife and 94 others outside the western Russian city of Smolensk as their plane attempted to land in heavy fog. A preliminary report drew no conclusions about what caused the crash.

Investigators have said at least two passengers visited the plane's cockpit before it crashed and others may have chatted on cell phones, possibly affecting navigation.

Edmund Klich, Poland's envoy to the investigation, confirmed last week that one of two voices in the cockpit not belonging to a crew member was that of the Polish Air Force commander, Gen. Andrzej Blasik.

Klich said that Blasik spent a few minutes in the cockpit and remained there until the end. "He wanted to know what the situation was," Klich said.

Klich said that psychologists were trying to determine if Blasik's presence in the cockpit pressured the pilots to attempt a risky landing.